Welcome!
I'm not sure that anyone can truly answer your questions for you except for yourself (and your wife, of course!). In order to decide where to put your money, you need to rank your priorities, and also look at your future earning potential.
If you want the $40,000 to grow and be used to FIRE, you should fully fund IRAs for you and your wife, and invest the remainder in taxable index funds (such as those provided by Vanguard). If purchasing a small house in the near term is your priority, you will want to put the $40,000 in a safe interest-bearing account such as a money market, CD, or an online savings account with a higher interest rate. As far as the car, I agree that you are better off buying a used car. Judging by your current expenses, if you start saving now, you should be able to save for a very nice used car without touching your $40,000 savings.