I realized that if I just minimize my 4 multiboxing slaves, they use 0% CPU and still work... and I can get normal FPS on my main screen...

However, after a minute or so, the characters will stop following, and then when they try to follow, they walk and get chucked back to there original place?

Try it out, run a few characters, minimize all of them apart from your main screen, and then make them follow you... It works, but after a minute you'll see what I mean.

Should I report it too WoW? Would it get fixed?