Don't know if this is a great thing or bad thing... haha but the fact that square is very lazy with their ports and what not, they never remake or recreate their system.
The IOS and Android ports use the PC version. If you would like to install mods, everything is setup the same way. For IOS you would need to modify the .IPA file via 7zip. To save yourself the trouble from installation errors later on, I'd recommend just opening the .ipa via 7zip and paste/replace the .lgp files. You can change the movies also after re decoding the video file etc to match the original properties otherwise upon boot, the game will load the logo and then crash when the first video is played. The .exe file can be modified via hex editor or applied with the patches, however i haven't tested it in game, but editing doesn't crash at all. If you'd like to see if the modified .exe actually works, the fastest way is to replace the battle characters, ie changing original cloud to hi_res cloud.
The folder structuire to edit these are ff7.ipa>>Payload\FinalFantasy7.app\ff7_1.02 \data\ Also to mention, there is no kernel file so you can't simple drag and replace for the battle names (fire fira etc)
Android:
You'd have to edit the Obb file and to do so is the same steps as opening it up with 7zip.
The file structure is as follows: ff7.obb>>assets\ff7_1.02\data\
For external textures, you'd have to place it inside the lgp for it to work.
Though the only downside to the mods is that it can be very laggy, and heavy on the gpu depending on which device your running it on. Alternatively you can optimise it for mobile os by reducing the poly count of the models etc and lowering the texture resolution.