Try to search on google free fonts for commercial use and check the license that the creator put up. I always do that when I'm looking for a font. Otherwise you'd have to pay a few bucks for the fonts
With regards to the cover, these two images look pretty dope. Maybe try to combine them into new design.
Good luck with publishing your book. Maybe at some point I'll ask you some advice as I am currently working on my own.
Thanks for the input. I'll be around whenever you're ready to pull the trigger on your book. I've published a few things so I'd be happy to offer any input I can. If you need a beta reader I'd also be happy to give you some notes.