ReverserBucket's first reply regarding OAA using FAA instructors is irrelevant. The course has CAA approval, has had it for years and will continue to have it. So far, there is no definitive evidence that EASA coming on line will undo OAA and I would imagine that CTC New Zealand has the same issue and Cabair in Florida does too.
The important issue here is how do airlines prefer modular training to be done. The only one I know of to have taken a public position on the issue is Flybe. Others may have stated positions that I am not aware of, but I am sure other members will pipe in about that.
Flybe will accept one FTO for PPL, another for ATPL theory (probably in recognition of the results at BGS), a third for CPL/ME/IR and a fourth for MCC. A better way to say this would be that they prefer no more than two FTOs for the professional flying training bits and this is probably allowed so that students of some reputable modular FTOs that lack MCC capability aren't ruled out of applying to Flybe.
One can find quite a few reputable modular FTOs that can offer CPL/ME/IR/MCC, but keep in mind that Flybe also require a JOC. I think you may be able to apply to Flybe without it, but must then complete a JOC if they hire you. I don't know if the mandatory JOC is still a Flybe requirement, as it's been a while since I was told this by a Flybe recruiter at a Flyer Show, so if anyone can shed more recent light on this, please do.
I recommend the OP see if anyone can add to the above and clarify further or even state the preferences of airlines besides Flybe before proceeding. This is mostly because Flybe aren't hiring much yet and I'd say 90% or more of their low hour FO hiring the last two years has been their own mentored cadets and the other 10% or so has been Jersey/Guernsey residents who have good training reports, but also have won the post code lottery, so to speak, when Flybe have had Channel Island base vacancies.
Ryanair hire low hour modular students who can fund a type rating. I don't know the percentage breakdown of mod vs. int at RYR, but their appetite for OAA grads seems voracious. Since the OP has done ATPL theory at OAA, perhaps he can enquire how many Waypoint guys are in their Ryanair figure. He would also be wise to ask the other modular schools he's looking at how many of theirs have gotten in at Ryanair. They will know because Ryanair sends them a reference request letter when applying for their new FO's airside pass.