Not eventually. Not in a tiny bit. ASAP. Now. Pronto. Why do you have 4 bettas in a 5 gallon tank? You are extremely overstocked.... better yet, why did your betta fish numbers go from 2 to 4? You were in a with a male and female in a 5 gallon as it was.
Right now, I'd almost say just go ahead and do 100% water changes every other day. You're at pretty much 1.25 gallons per betta. Get your girls their own tank. If you want them all in a tank, I'd advise a 10 gallon divided 3 ways. Sororities are risky business. Bettas blow bubble nests; it's what they do. My male Kaimar was blowing a bubble nest in a disgusting cold cup when I bought him. I highly doubt they are any where near ready to breed, and neither are you.