Hi Cbell,
I did BFL for awhile and actually the part that I really enjoyed was doing his version of cardio - the all out 20 minute interval. I felt so incredible after I would do that in the morning. I would just use my own music and do step - repeating the 4 - 1 minute moves at increasing intensity. So like level 1 is step up and kick, 2 is around the worlds, 3 is over the tops and 4 is power 7's. Then for my last blast I would do plyo jacks. Not the most exciting thing but it was only 20 minutes and I found I could really concentrate on working instead of trying to follow a video. Also, one thing that really came through with that is what Bill says about doing stuff at YOUR 50%, 60%, etc. and no one else's. So it's not like you're looking at a video and sometimes thinking - "Oh, this is hard, I can't keep up with her pace." You're just really pushing yourself. It was a nice change. I went back to Cathe's cardio but I still do the BFL on the step every once in a while. One concern I have with you tacking on the power yoga is over use of your upper body. You will be lifting really heavy on your lifting days and maybe you should just totally rest your upper body instead of using it with the yoga. If you just love the yoga and can't live without it then I'd do it on a weight day. If you're doing it for the extra cardio, so just do more than 20 minutes. If you are going to substitute Cathe cardio for BFL then CTX is the way to go because it is so intense. Other good ones are the first cardio portion to Body Max and part, or all, of IMax.
I personally had a hard time with the weights - I like to work my muscles so they feel totally pumped up - a feeling I always get with Cathe and didn't really get with BFL. I also felt that it was really difficult to go as heavy as I would need to do the heavy reps at home - which may be why I didn't feel the pump. I'm curious if Trevor was working out at home or at a gym. It seems like it could be much more effective at a gym or with a spotter.
I think it's great that you're trying something new and you should see results just from changing your routine. I agree with what Trevor said about not having to follow it 100%. You have to do what works for you. Good luck!