What do you know about AR15's? They are banned. You know that.
The reason AR15 exist is the interchangeability of parts. What advantage do you think you can get from that?
I am actually quite surprised that many new gun owners (no offense) are looking for the same as you are looking for. But what does that actually means? Really nothing, todays prices in Canada to build your own rifle is really a big joke. This was not what AR's were meant to be.
The idea was to build a milspec rifle at your own budget and that really is what it says. Some build one over the top but mostly AR's is more of a budget situation.
You want a top charging handle, easy to answer that question, your eyes will show you. You want FA, same story. You want an upper and lower with one pin on the front and one on the back and you can interchange it with AR's upper and lower - hahaha. I actually saw a receiver (upper and lower) on the EE yesterday which meets that requirements. I call that asking for trouble - mods should remove that one in my opinion.
Dude, educate yourself.