gcarn,

I can't 100% tell you if 10 days in ten working days or 10 straight days, sometimes this can depend on where you submit your papers, but allow for a couple of extra days.
For the UK CNI, you give details of where you are going to get married (in Phils), but it is only the location, ie: town/church/municiple nothing more in my experience. They don't need to know your inside leg measurement Just make sure you take your original copy of your final decree of any previous marriage as the DO need that, plus birth cert, details of your fiancee again, basic details that you should know anyway.

As for your last point, when you go to the embassy to exchange your UK CNI, I guess they already know your intention to marry as it's a pointless exercise otherwise.

Good luck, just be organised and leave nothing to chance.