Question Modding barn animals - a couple of questions!!

[KramplessHeaven]

Good morning!!
Me and my partner have recently started working on our very first mod for Stardew Valley adding some brand new barn animals to the game! We obviously want them to be as good as possible and even though we have many ideas I'm still not completely familiar with the game's code [especially after the last update, as most of the tutorials cover the older versions] and I'm not sure how to make everything work.

• regarding animal sprite sheets, there doesn't seem to be a rule for the size of the sprite sheet. I know that the sprites themselves are 16x16 or 32x32 for Coop and Barn animals respectively, but the full sheets differ - barn animals' ones are 4x5 sprites [or 128x160 pixels], but coop animals are either 64x112 pixels [and 4x7 sprites ] or even 64x224 [for Baby White Chicken, Baby Golden Chicken and Duck] [4x14 sprites]. My question is, would it be possible to create a sprite sheet for a barn animal with more than twenty separate sprites on it? Would it be possible to add some sort of animation, for example for lying down? [something like the animations for pets, only for barn animals?] And is it possible to code when an animal can actually perform an animation? [I'm thinking something like the Duck's swimming animation which is logically performed only when the animal's near a body of water.]
• where is the animal data stored? I unpacked the .xbn files in the Content folder of the game and even though I have access to the Animals folder now there are only sprite sheets in it, with no actual code? The Wiki mentions a file where it used to be stored on version 1.5.1, but even that isn't the full data I think, as while browsing through other mods I've noticed codes changing things like Shop price or icon. Is there a file where the data can be changed or even just checked?

Thank you all in advance for help!! :]]