Pokemon Gen 3 Puzzle Walkthrough

Pokemon Gen 3 Logic Puzzle Walkthrough:
1) Since the only places grass-types can be are in the corners, and Grovyle's evolution (Sceptile) has to be in the same diagonal as Cacnea, Sceptile has to be in E5.
2) The DNA Pokemon is Deoxys, so Deoxys is in A3.
3) We know from Cacnea's clue that no single-type Pokemon can be adjacent to each other. so the two starters must be in C1 and C5. We also know that Treecko is not one of the starters, since Treecko is a grass-type and would have to go in a corner. Sceptile's clue tells us that no fire-types are in the first column, so Torchic cannot be in C1. The only remaining starter abot to go in C1 is Mudkip, so Mudkip is in C1. This also means Torchic is in C5, since Mudkip has already been used and Treecko cannot go there.
4) Based on Mudkip's clue that there are exactly nine single-type Pokemon, and Cacnea's clue that none of them can be adjacent to each other, we can deduce that there is only one possible arrangement of the single-type Pokemon in this 5x5 grid. Assuming that each 'O' represents a single-type Pokemon and each 'X' represents a dual-type Pokemon, the arrangement of single-type Pokemon must be as follows:

O X O X O
X X X X X
O X O X O
X X X X X
O X O X O

Based on this model (which I will refer to from now on as the 'single-type model'), we can conclude that Jirachi must be in either B3 or D3, since those are the only spaces in Deoxys' column that aren't allotted to a single-type Pokemon. However, we know from Sceptile's clue that no type is adjacent to itself. Since both Deoxys and Jirachi share a psychic-type, Jirachi cannot be in B3. Jirachi must be in D3.
5) Now that Jirachi has been placed, we know that Electrike must be in either C3 or E3, since those are the only cells adjacent to Jirachi that a single-type Pokemon can occupy based on the single-type model. It is hinted that Electrike is in C3, since it is also a basic-stage Pokemon and would fit with Mudkip's clue that its row is all basic-stage Pokemon. However, more concrete proof can be found in Deoxys' clue, which states that there are no electric-types in row E. This means that Electrike cannot be in E3, so it must be in C3.
6) Electrike's clue tells us that Treecko and Grovyle are not in the puzzle. Based on this, as well as the fact that Cacnea and Sceptile have already been used, we know that the only Pokemon that are allowed to be in the corner are Seedot and Shroomish. This is because the single-type model shows that all the corners are occupied by single-type Pokemon, and the only single-type grass-type Pokemon that have not yet been used are Seedot and Shroomish. Since Torchic's clue tells us that it shares a column with Shroomish, we can conclude that Shroomish is in A5. The only remaining single-type grass-type is Seedot, and the only corner left is E1, so Seedot is in E1.
7) Based on Shroomish's clue, we know that Mawile must be in either B4 or D2, since those are the only spaces on its diagonal that have not been used. However, D2 is adjacent to Jirachi, and Mawile and Jirachi cannot be adjacent to each other since they both share a steel-type. Mawile must be in B4.
8) We can now place Camerupt as being in either B3 or B5 based on the info from Jirachi's clue. However, we know that Camerupt cannot be adjacent to Torchic since they are both fire-types, so B5 is ruled out. Camerupt is is B3.
9) Mawile's clue tells us that a final evolution rock-type is in B2. There are only three final evolution rock-types in Gen 3: Aggron, Cradily, and Armaldo. Jirachi's clue tells us that Aggron is not in the puzzle, and Cradily cannot be in B2 as it would be adjacent to Cacnea, and they are both grass-type. The only remaining candidate is Armaldo, so Armaldo is in B2.
10) Based on Torchic's clue, we know that Relicanth is somewhere in column B. Once Armaldo has been found, we can rule out A2 and C2, since Relicanth cannot be adjacent to Armaldo on account of both of them being rock-types. That leaves D2 and E2 as the only remaining options. However, since both Relicanth and Mudkip share a water-type, Relicanth cannot be in D2. Relicanth is in E2.
11) Before Relicanth and Seedot were discovered, we could place Carvanha in either A4 or C4. Although Carvanha being in C4 would fit with Mudkip's clue of row C having only basic stage Pokemon, its location was not certain until Relicanth and Seedot were placed. Seedot's clue tells us that Relicanth and Carvanha share a diagonal. This leaves C4 as the only possible place for Carvanha to be, so Carvanha is in C4.
12) As soon as Camerupt was found, Hariyama could be placed in E3. This is because at that point in time, the only remaining space for a single-type Pokemon to be was in E3. hariyama is a pure fighting-type, so Hariyama must be in E3.
13) We know from Camerupt's and Hariyama's clues that Hariyama is adjacent to both Sableye and Spheal. We know that the stage one ice-type is Spheal because the only stage one ice-type in Gen 3 that has two types is Spheal. At this point in the quiz, we know that the rest of the Pokemon that need to be found all have two types, which leaves Spheal as the only possibilty as a stage one ice-type.
Their possible locations are D2, D4, and E4. However, both D2 and D4 are adjacent to water-types (Mudkip and Carvanha, respectively). This rules out Spheal for those cells, since Spheal is part water. Spheal must be in E4. This leaves Sableye as being in either D2 or D4. D4 is ruled out, since both Sableye and Carvanha share a dark-type, so Sableye is in D2.
14) We can deduce that the remaining ice-type in column 4 is either Sealeo or Walrein, since they are both evolutions of Spheal. However, Walrein has been explicitly mentioned in Camerupt's clue, so it is safe to assume that it is Walrein and not Sealeo. We also know that Walrein cannot be in D4, since it would be adjacent to two water-types (Carvanha and Spheal). Walrein is in A4.
15) Camerupt's clue tells us that Walrein shares a diagonal with Taillow, meaning it could be in either D1, C2, or B5. We know it can't be in B5, since Armaldo's clue tells us that it must be adjacent to Gardevoir, and there are no open spaces adjacent to B5 for Gardevoir to go into. We also know that Seedot can't be adjacent to any flying-types, as stated in it's clue. That leaves the only remaining space as C2. Taillow is in C2.
16)We know from Armaldo's clue that Gardevoir is adjacent to Taillow. The only remaining spaces adjacent to Taillow are B1 and D1. However, Spheal's clue tells us that Sableye cannot be adjacent to any fairy-types, since that is the one type it is weak to. Since Gardevoir is part fairy, it cannot be in D1, so Gardevoir must be in B1.
17) Since all the spaces for single-type Pokemon (as shown in the single-type model) are now gone, and there are two legendary Pokemon yet to be found (Armaldo's clue states that there are four legendaries total, but two of them, Deoxys and Jirachi, have been found), we can conclude that the two remaining legendaries are both dual-types. The only dual-type legendaries in Gen 3 are Latias, Latios, Rayquaza, and Jirachi. Jirachi has already been used, and Armaldo's clue tells us that Latias does not appear, leaving Latios and Rayquaza as the two remaining legendaries. Relicanth's clue tells us that no legendaries are adjacent to each other, and that Sceptile is not adjacent to a legendary, leaving the only possible spaces for the legendaries as D1 and B5. We can look to Seedot's clue once again to help us find the location of Rayquaza, as we know from the fact that it cannot be adjacent to any flying-types that Rayquaza cannot be in D1. Therefore, Rayquaza is in B5. This leaves the only remaining space for Latios at D1.
18) From Carvanha's clue, we know Metagross must be in either A2 or D5. Since A2 is next to Deoxys, and both Pokemon are part psychic, Metagross cannot be in A2. Metagross is in D5. Latios' clue means that Sceptile cannot be in D4. The only remaining space is at A2, so Salamence must be in A2. The remaining space, D4, goes to Dustox.

Tl;dr version:
1) Sceptile in E5
2) Deoxys in A3
3) Mudkip in C1 and Torchic in C5
4) Jirachi in D3
5) Electrike in C3
6) Shroomish in A5 and Seedot in E1
7) Mawile in B4
8) Camerupt in B3
9) Armaldo in B2
10) Relicanth in E2
11) Carvanha in C4
12) Hariyama in E3
13) Spheal in E4, Sableye in D2
14) Walrein in A4
15) Taillow in C2
16) Gardevoir in B1
17) Rayquaza in B5, Latios in D1
18) Metagross in D5, Salamence in A2, Dustox in D4