1) Depends what you mean by summon. If you mean summon skills like in the earlier Final Fantasy games, where the summon appears and does damage and dissapears, then that's just a case of making a skill that includes the summon in the battle animation. If you want something that comes into the party for a small amount of time, something more like the more recent Final Fantasy games, then it is possible but it is a lot more difficult to do. Especially if you plan on having the whole party replaces by just the summon itself and then plan to bring the party back if the summon dies. Having the summoner be replaced by the summon would be a little easier to manage I think. Ther are a lot of summon tutorials out there, so it should just be a case of using Google to find one.
2) Transforming into something is possible, it can just be glitchy sometimes. If you search Google for tutorials you can probably find one, transformations are pretty popular. Changing an enemy into a toad would be possible, but it would require making a toad form of each enemy as a seperate enemy and would be very time consuming. Unfortunately, I don't think I have ever seen a tutorial for a toad form, but I assume it would be similar to having a hero transform into something.
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