What size room are we dealing with? Open to other rooms or sealed off? How deep do you want the subwoofer to play? How loud?
I generally avoid subs from primarily speaker companies, I also would generally avoid subs with 8" drivers, unless perhaps you have a very small closed off room and placement of a sub very difficult otherwise. I'd prefer a ported sub over sealed sub generally, too, they're simply more efficient (and the old adage of sealed is better for music really doesn't apply with a decent sub design, more an old audio myth), but generally a ported sub is larger than a sealed sub. They likely also have a more limited frequency response to provide a crossover at 200hz.
The 7000i's are small speakers with small drivers, which is probably a bigger issue in general for lower end/bass response than the sub itself. They are spec'd 95hz-20khz but no particular specification on what range of dB that is (+/- 3dB is somewhat standard, but sometimes its -6dB), they're rated 6 ohm and of relatively low sensitivity, too. I'd simply want more capable speakers up front particularly and use something like those as surrounds. You could probably cross these fairly well with that spec at 120 or so. A possibility for sub localization exists the higher you cross over to a sub, and 200hz is quite a high crossover point, plus some subs drop off quite a bit by 200hz.
The BK P12-150SB I don't see, but do see a P12-300SB, the latter using a 12" driver and 12" passive radiator, so is a sort of ported design but yielding a smaller box (altho generally two 12" passive radiators for a 12" driver would be more the norm). The XLS300 is a sealed 10" with decent extension (how low it goes). I don't see specs for the upper end of their range coverage, tho.