Thanks!! I knew we needed to wait until closing, for sure! I am just not sure if we should buy before the mortgage line shows on our credit reports (go down the day or weekend lol) after closing to buy, or wait until the mortgage is actually reporting. Any time we have added a new trade line our fico takes a hit for a short time, but I know mortgages help scores so I am stuck on which is better as far as credit score goes.
Will our scores take a short hit from the mortgage reporting as a new trade line, or will they go up because we finally have a mortgage account on our credit reports? We have never had a mortgage loan so I am confused how it will affect our scores 
After you mortgage closes and you have keys in hand (which you already do-lol) then you should go after that vehicle before the mortgage hits the CR, usually that tradeline will reduce your points because of the current debt vs what your balance is on the debt (brand new).
Thank you! That is what I wasn't sure of! I didn't want to run out after closing and buy a car then have the mortgage report and raise our scores higher to help with interest rates
I am sure eventually it will raise our scores, my vehicle just isn't going to wait for that to happen 
Our monthly payment is only going to be $200 under what it currently is, if that makes a difference in the discussion
We also plan to just keep the same amount we are paying now on automatic draft so in the end, the amount we pay monthly toward the house is not going to change after the mortgage is fully in our name anyway.
The only way the amount we pay/month is going to matter is if we lease or finance through a dealership. Our credit union is funding our mortgage so if we use the credit union, or the bank where I work they are already going to know we have a mortgage getting ready to report. Both the credit union and the bank where I work will have the same interest rate regardless of whether there is a change to our scores, or not.
Leasing/purchasing through the dealership interest rate will change, though, if our scores take a dip once the mortgage reports. The only reason we would use the dealership financing is if they can give us a lower apr than our credit union or the bank where I work, or if we decide to lease a vehicle rather than purchase. My husband's scores are much better than mine but they are already very borderline since we had a lot of rebuilding to do after a bad deployment/pay issue before he retired from the military. Any reduction, even small will bring them back under the "good" range to the "fair" range (Exp and Eq are hovering just under "good" by about -10 points and TU is over "good" range limit by about +15 points).
Hopefully next month they will all be up in the "good" range so we have more options for financing. I know we can finance through the bank where I work at 4%, but if we can get lower than that through GM (we plan to buy a Suburban), it will help with the monthly payment because Suburbans ain't cheap lol
Thank you everyone for your help and insight! Credit scores can be such fragile and unpredictable things that sometimes I'm afraid to even breathe the wrong way
After working so hard to rebuild I don't want to make any uneducated decisions that will cost us money unnecessarily