Hello, I'll answer your questions here:
1. Yes. It can.
2. Yes, you can.
3. Yes, of course.
4. Yes, very much.
5. Nope, you gotta use additional plugin for Heart HP.
6. Every game engine rely on parallel. It's called "parallel" in RPG Maker but it's actually "update" which happen on every frame. The conception "parallel causes performance issue" is incorrect, it really depends on what inside that parallel event. Even if you don't use parallel, it's likely the plugins you're using are using it backend.
7. Yes, it supports that.
I don't know about Chrono Engine, but my RPG Maker Action Combat is an upgrade to RPG Maker MZ, it brings many eventing features to the engine, which allows you to create the thing you want using eventing. Most of the things you asked here actually had video tutorials already. You can check them out on my Youtube channel.