What you suggest sounds good for a start, I encourage you to try, it'll probably work.
No need to buy anything, all this should be working, just a matter of proper configuration. I suggested to cut down just for a test, once the bare essentials are working you can add gear piecemeal and adjust configuration as necessary. Do it step-by-step, there's hardly any circumventing that time and effort. Unless you're ready to throw out everything and buy a complete system or pay someone to work it out for you and integrate all your gear into one system. There's nothing wrong with your gear (I reckon), but careful planning and diligent/precise work is needed to get it all to work as a system. Hope this helps.