Overall it sounds like your ideal path is a decent one. I will say that I don't think you need to acquire a type rating on your own.
For the basics though, you want to choose an affiliated college with an aviation program for training or join the military (WMU meets this requirement). Aviation related degree will come with that, although just having a non "basket weaving" degree is the most important part. You understand that GPA is important.
You don't have to limit yourself to only doing volunteer work for the flight department. I don't know if WMU has a flight team but that could be something to look into (it's not aerobatics), it gives more flight experience while a good learning opportunity. Outside of that, Delta loves community service work too.
I don't think the propel program can hurt you, if you can get accepted I'd go all in for it, but you can still get hired even if not accepted into that program.