As a Greninja going into this MU i'd probably lean towards banning tri-plats. If a Greninja recognizes all his options on this stage, it's actually not a bad one for him, just he has better ones at times and I'd say Mario benefits from tri-plats a lot more than he does in general.

As a Mario if you do go to these stages, just watch out shenanigans he can do with uptilt footstool and down throw to force you into platform combos. He has good platform movement too and can get to top plat quickly and go from there. Be wary of him having the option to recover high to a platform with hydropump as well and factor that into trying to edgeguard him.

I'd probably prefer not to go to Smashville either since the stage doesn't give me as much space to run away from Mario and
play around his options as i'd like.

Lylat is a usual ban for most Greninja mains out there since shuriken camping can be lessened depending on the MU and if the Greninja doesn't move around the stage along the tilts while he tries to do so. But a Greninja by the name of Keekay told me he actually prefers Lylat > BF & SV against Mario.

He says Mario can have a hard time reaching Greninja on Lylat as the stage can help Greninja move around so much if they are comfortable. Anywhere on the stage Greninja can SS to platform which is something he can't do on BF because only 2 plats near ground level. On Lylat he'll land on one of the 3 platforms. Greninja doesn't struggle recovering as much as other chars so hard to get gimped by Lylat. Stage tilting can make certain moves or hydropump safer for him. It's also easy for Greninja to chain upairs on this stage because of the platform layout.