How to run a Private Progression Server?

[CheshireKas]

As it says on the title. I have a small group of friends (max online at a time would probably be something like a dozen), and I'm wanting to potentially run a progression server up through BFA. We had a CMangos classic repack, and that was fine and fun, but we do want to experience the content of all the other expansions before skipping through to BFA. To my knowledge, most old content in BFA repacks is typically highly buggy, so it seems a progressive server might be the best bet, but I'm lost on how to try to do that. I would def want us to be able to keep our character info (talents, achievements, etc) through expansions, and I think playerbots could be fun. Of course, I could mess with enemy health and attack to rebalance dungeons and raids, since we have such a smaller player base.

Any thoughts on the best way to go about this? Any help is appreciated.