>Where do I find the TW3 witcher school armors?

Bear School (COMPLETE):
1 - Armourer, Oxenfurt
2,3,4 - Blacksmith near Bridge to Kaer Trolde
Cat School (COMPLETE):
1, 2 - Vendor and blacksmith in Backbough
3 - Crow's Perch Vendor
4 - Lindenvale
Griffin School (COMPLETE):
1,2 - Midcopse, Armourer
3 - Hierarch Square in Novigrad
4 - Hattori (It's name of Vendor, basically that elf which gives you quest Of Swords and Dumplings - You need to finish that quest in order to get the map)
Wolf School
1 - Merchant, Lindenvale
2 - Kaer Trolde, Armorer
3 - Kaer Muire
4 - Hattori or Armorer in Hierarch Square in Novigrad

Pictures of all the different Witcher's gear with upgrades:
http://www.gosunoob.com/witcher-3/best-armor/

Viper School:
There's no map or upgrades and it gear set has only two swords, it's like starter Witcher's gear. You can find it in White Orchard. You can start the quest in castle ruins by searching one of chests.

>Where should I start on the books?

In chronological order:
The Last Wish
The Sword of Destiny
Blood of Elves
Times of Contempt
Baptism of Fire
The Tower of the Swallow
The Lady of the Lake

>Are all the books translated?

For English, all up to Baptism of Fire are translated, the last two are currently scheduled for 2016 and 2017 respectively.
There are complete translations of the series into German, French, Russian, Portuguese and Spanish.

>Are the books essential for the enjoyment of the games?

No, but the books take place before the events of the games and there are many in-game references to the books. It's recommended to read them if you enjoyed the games.

>Does the TW2 do a recap of the first's story?

Yes, it does in one short movie (spoiler alert):
https://www.youtube.com/watch?v=ZHwa-7LBfV4

There is also a short movie explaining what witchers are:
https://www.youtube.com/watch?v=AzfFPONyjSw

>I'd like to play them in order, but all I hear about the first's combat makes me worry that I'll be alienated by it before I get into it.

It's all up to you. Some people don't mind the combat, some can't get over it. But you should give it a shot, especially according to the fact that the plot is, in the eyes of many fans, better than in TW2.

You could always just play it on easy to finish the combat sequences quickly.

TW1 in image form, compliments of anon:
http://i.imgur.com/gouGM0m.jpg (although FCR is listed in the image do not use it as it can cause gamebreaking issues with monster spawns)

Recommended Mods for Witcher 1:
Scabbard Mod - Adds scabbards for the swords http://www.moddb.com/mods/scabbard-mod/downloads/scabbard-mod-v104


Rise of the White Wolf - Improves UI and Textures http://www.moddb.com/mods/the-rise-of-the-white-wolf-powrt-biaego-wilka/downloads/en-rise-of-the-white-wolf-fcr-version

Make sure to install the Scabbard Mod followed by Rise of the White Wolf. Also get hold of the latest patches for these mods which are available on Moddb as well.

Witcher wiki:

http://witcher.gamepedia.com/Witcher_Wiki

Unofficial book translations:

http://forums.cdprojektred.com/threads/16494-Our-Community-Fan-Translations

Map of the Northern Kingdoms:

http://i.imgur.com/BrKZB20.jpg
http://i.imgur.com/ynRQVob.jpg
https://i.imgur.com/ezypmy2.jpg

TW2 saves for all possible outcomes and decisions:
http://forums.cdprojektred.com/threads/30709-(SPOILERS)The-Witcher-2-Save-Game-Files