Dual handle shower valves haven passed plumbing code for over ten years. That's why you don't see two handle valves much anymore.
If you use a two handle valve, a balancer can be installed ahead of it if it's being inspected. However, it makes much more sense to install a new pressure balanced single handle. That is the current product being installed, and parts are easy to find for those.
Can you mix brands on a single installation? No. The valve trim needs to be the same brand as the body of the faucet.