No idea. I'm not sure exactly how long Tainted will be on hiatus. All I can say for certain is that at the least, not until after finals. Yang Child will also be on hiatus during finals week as it is every finals week. Chapter 2 of Tainted is short, so it shouldn't take long to draw. It's just a matter of finding time. 5 to 6 weeks would be my best guess.
Guest strips from anyone would be greatly appreciated, so if you or anyone would like to do one, by all means, feel free. I love fan stuff.
As for BESM, you've got lots of options. I'll explain them to you at game on Friday since I find it easier to do it person.