Haggis,
Reading through your posts, I can't helping thinking that you are a little confused, and not quite sure what the various licenses and ratings are all about, or which ones you want/need. Without knowing this, it's impossible for you to make a decision about the best way of obtaining those licenses/ratings.
I'm going to try to pick out as many of the inconsistencies in your posts as I can, and correct you as best I can, then I'll have a go out figuring out exactly what you're actually trying to do.
In your first post, you said: "my goal is to obtain a frozen CPL". There is no such thing as a frozen CPL! Do you mean a frozen ATPL? To clarify the terminology a little: there is, officially, no such thing as a frozen ATPL either, but it is a term which is commonly used to mean a CPL/IR, with passes in the ATPL exams, and sometimes (but not always) an MCC.
"I believe that the CPL and the ATPL have now been merged and it's only the matter of experience that now separates them". This is a bit of an oversimplification. Before you can do the CPL, you must pass either the CPL written exams, or the ATPL written exams. The most common course of action is to do the ATPL written exams. If you do this, you can then get a CPL and an IR. It is then only a matter of experience before you can qualify for an ATPL. (Over-simplification here, but close enough for now.) However, if you were to do the CPL exams instead of the ATPL exams, then you can't upgrade your CPL to an ATPL without doing more exams first. So what you are saying is not quite right.
Next, your plan includes PPL, Night, IMC, Multi, ground-school and IR. But it doesn't include a CPL. This seems to be a bit of an oversight on your part? (Also, as Ham says, you can't actually do the IR test in America - but there is nothing to stop you doing most of the training for it there, and returning to the UK for the final few hours, and for the test.)
Now, putting all of this together, I would guess that what you want is a frozen ATPL? (Can't really tell, since you don't say what this "once in a lifetime opportunity" is.) In that case, your plan all sounds pretty good, except for the lack of CPL. You might also benefit from the MCC, but this is not vital, and it will depend on what opportunity you've been offered.
I hope that has clarified things for you.
FFF
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