There is a RPGmaker autotile importer for unity to import tileset from RPGmaker. But you could also change the grid size to 24px for using the autotiles.
A5 are simple 48px textures. You don't need a change there. A1 is animated water and also a autotile except the waterfall. You can split the waterfall vertical 3 times for a smooth animation. I hope I could help.
