Kev - Sorry to hear about the divorce and the BK. But sounds like you are on the right track. A score of 700 is great after going through all that!
The answers to your questions ... all depend. If you are focussing on rebuilding credit and you lowered the limits on WalMart etc, just make sure you keep your balances correspondingly lower (under 35% of the credit limits). If you charge up to the new low limit, it will hurt.
Too much available credit (i.e., lots of credit cards with sky-high limits) has no impact on your FICO score (as far as we know). HOWEVER, if you apply for a mortgage, the lender will take into consideration how much potential credit you have. Lenders can be scared off if you have the ability to charge up high balances. In that case, you didn't shoot yourself in the foot by lowering the limits.
Why did CapOne raise the rate? I'd call and tell them you've been a model customer for 6 years, paid on time, etc., etc., and ask for a rate reduction. You've done this before so you know it's possible. Because you are in rebuilding mode, I'd keep the CapOne card for the length-of-credit-history factor.
Beware of Orchard Bank cards. Many of their cards have an annual fee, a monthly fee, an application fee, a credit limit increase fee, etc. etc. If you haven't received your first statement, you may be in for a rude shock.