She said that if she pays to get it fixed, she expects to keep it. 

Class D,F should be all electric to minimize fire risks (leaving stove on etc) a Class A properly might expect a gas stove.

Even if the #s are good should I expect these properties to be less attractive to buyers because of the flood liability in the future?

If you have a C property in a C area expect to pay a lot as a % to manage.There is a near 100% chance I know of the property (and know the owner, what they paid, what it was offered at, when they bought it, etc.).

How do  you expect to force appreciation $20K without any repairs?

Once you sign the lease, there is an expectation that all the rent will be paid each month regardless of if you find other people.Good luck.

It’s a mixed bag one as you expect it could take t months to a year and things change constantly.

Home builders have pulled back to support levels and I expect a big bounce in the next month.

If you go with one of these three don't expect much room for profit if any.Best way I know of is to do direct mail or door knocking.

I would not buy something now with the expectation of the same amount of appreciation we saw in recent years nor would I expect a significant increase in market rents for any particular neighborhood.