1. In broad strokes, I have the full 5 game narrative arc planned, yes, although things obviously always shift a bit in development. But some general planning was needed, because there's an overarching story for the whole thing. That said, Chapter 3 is going to be a bit of an oddball, because it's somewhat separate from that. SOMEWHAT, but not entirely.
2. We'll see. A bundle is certainly a possibility, but that's a loooong way off. I certainly wouldn't hold off buying the games in hopes of getting a bulk discount.
3. It definitely gets easier and faster to do x or y as I go, and as I learn. But also, I want to make each game more sophisticated, more interesting and hopefully a little more fun than the last. 3 is going to be a LOT more complicated than GT: more content, more stuff going on in Haven (especially eventually with the addon packs), and just a lot more refinement to little things here and there. If I just cranked out GT, but with new setting and species, I could have finished a lot sooner, but every time I want to try out new things I wasn't able to do before.
I don't want to get expectations TOO high, it is an RPGMaker game at the end of the day. But there are a lot of neat little things going on with 3 that GT didn't have. I just spent a day, for example, setting up an instant retry option on a mini-boss, something I've never done before and something RPGMaker surprisingly has no built-in system for, and which is surprisingly difficult. This is definitely something people are going to die to their first few tries though, AND it has a fancy lead-up to it, so I didn't want to subject people to having to watch that same leadup over and over and over and over until they want to throw something. Now it's a nice clean "try again", like a real game!