Can a bankruptcy help push for a real modification and or a lower interest rate (10) so I will be able to make future payments

Probably neither. With a bankrupsy on your record you will noyt be a candidate for a loan mod or a lower rate. You need an accountant to go over your finances to determine the best route.

In some states you can keep your home in bankruptcy.like florida. And, in certain types of bankruptcies, you can pick which accounts you wish to continue to pay on. If you file, make sure you keep any account open that you have a good payment history on... say you have a credit card in which you have never missed a payment and you have only used 25-35% of the allowed amount, keep that one, don't file it... you'll have 'good" credit a lot faster than you think. I filed, keeping 3 accounts that had excellent payment histories and in 7 months i had a good enough score to buy a car at 7 percent interest rate.

First no you can not file some debts and not others, esp filing some credit cards and not others, If you do the ones you did file on, if they find out, can come back to ask for the bankruptcy to be over turned because you are treating two creditors in the same class differently.

You can re-affirm some debts, like house or cars but will have to be able to make those payments