OMG, yas. Read the Young Avengers and come to the gay, jewish, magical side of the force.
No shade, but Zub can have Prodigy. As long as Billy, Teddy, Cassie and Tommy (I'd say Eli too, but that's a little more complicated) are secured for a YA relaunch, I'm fine.
There is room for anything Marvel wants to make room for. They relaunched the Great Lakes Avengers not too long ago, for god's sake.
Heinberg's run is essential, so I'm glad you're checking it out. Young Avengers Presents was a mini-series of one-shots focused on each member that was published while Heinberg was on a break from comics. It's not absolutely needed for you to understand his run, but I would recommend because there are some special developments for the characters in those issues. I didn't read Mighty Avengers so I can't speak on quality/necessity, but I think the only real connection they had to the YA was that Cassie and Jonas were a part of the roster.
And there are also other YA books, in case you're interested. We've had Young Avengers/Runaways: Civil War, Young Avengers/Runaways: Secret Invasion, Young Avengers: Dark Reign and Young Avengers: Siege (that was a one-shot, I believe). As you can tell, all of those were tie-ins for events and I don't know how familiar you are with those, but I read all of them before reading the actual events and, honestly, it wasn't hard for me at all to keep up. If you're just interested in reading more about the characters, I'd say go for it.
I'm happy for Kate, but I wish the other members would get to appear in books as much as she does. Anyway, I'm looking forward to this. Sounds cool.