1. Do you have a GBA and want to buy JJGBA (If you don't, don't waste time on this.)

No, and no.

2. If you had it, should you make a tileset of it?

I think it would be fun to use some of those tilesets in JJ2, but I suspect what you mean is making a tileset to use in JJA, which I doubt is possible.

3. If you had it, do you like it (or, just the question: Do you like it, and so no, what not?)

How would anyone have it already?

4. (The last, don't be barf about this quiz) JJGBA, do you name this a "adventure game", "Puzzle game", "barfing game for all zoinking moo foos", or "A roleplaying-game"?.

Yes.