Good evening, everyone!
I'm currently in the midst of buying my first house.. I have already submitted the loan application and have gotten back my approval for my amount and interest rate. At this point, I'm just waiting to find the right house and will lock in my interest rate at that point and sign the appropriate papers. In the meantime, I'm debating on when the best time will be to apply for a new credit card in hopes to have a larger credit amount and take advantage of the cash back options available, such as the one with Chase Freedom credit card. My Equifax FICO score has already dropped from 766 to 757 due to the loan app, not sure what my TransUnion FICO is at (was 756), and my Experian FAKO has dropped from 766 to 748.
Should I go ahead and apply for the Chase Freedom Card (and maybe Navy Federal Credit Card) now so that I can utilize the credit card immediately after purchasing the house and taking advantage of the cash back for home repairs, or should I wait until I find the house I want and get a mortgage added to my credit report? Furthermore, if I do apply for a credit card now, will that hinder my confirmation on interest rate when I lock in on the house? Or if I wait to get the credit card after I buy the house, how long is the approximate wait on the mortgage being "posted" to my credit reports?
Multiple questions, I know.. sorry! Please point out anything I might have missed, though. 
Well, from what I've read it is not a good idea to get any more credit and/or debts if you are looking for a home (unless of course the mortgage person tells you too). Underwriters do not like to see changes in your credit profile that could get you into trouble later on after they have approved you for a mortgage. There have been horror stories of couples going out to buy furniture for the house they are about to close on, only to find that the company pulled their credit again prior to closing and since there were unfavorable changes to the report, the loan gets pulled from under them.
Hopefully someone else with more experience with this topic will post, but my suggestion would be to hold tight until after you close, and then apply for other credit.
Current Score: Eq: 823 Tu: 830
+1 Do NOT apply for ANY credit until you have closed and the loan is funded. You don't want your scores to have any risk of being lowered. Lots of folks are having trouble getting loans now and if you've been approved treat it like gold...or platinum... or whatever is hot right now. 
Good luck and happy hunting!!
Thank you for your input, everyone.. I had a feeling this was the answer, but just wanted to make sure.
I will wait until after closing to apply for a credit card, then. Should I wait until after the mortgage loan hits my credit report to apply for a CC, or should I just do it right after since the loan might take a few weeks to post?
Thank you!!
Depending on your current mix of credit and AAoA, the new mortgage will most likely lower your score a little bit (maybe 10-15 points). Keep in mind it usually takes 2-3 months for the account to hit your report (not weeks). The lender will not report to the CRAs until after a couple payments have been received.