No reason why they won't bear fruit assuming all growing needs/conditions are met but what they will be remains to be seen since you were growing hybrids. Since you have the room and the time, let them grow and see what you get.

Enjoy your tomatoes.

Dave

PS: I linked some previous discussions about volunteers below so you can read what others are doing with theirs.

Here is a link that might be useful: Discussions about volunteers

I had a tomato plant growing in my flower bed last year that was a volunteer, probably from my compost. It was one of my best producers.

The only problem with volunteers is you may not know what it is if you have several varieties. Otherwise you are better off since you will be selectively picking plants that thrive in your local conditions. I tend to be OK with the seeds in my compost since they are usually easy to weed and provide rescue options if you really screw up and cook them in a cold frame or some such like my friend did. I gave several volunteers to him one of which was a very recognizable brandywine with a potato leaf.

I adopted too many volunteers last year and they didn't produce well at all. I'm on a strict no-volunteer policy this year...

I offered volunteers on freecycle and people came immediately from the four corners of the earth to snag them. Sheesh - it was like a stampede! I am told by "volunteer fans" that these produce well and the varieties are all over the place. For my own garden I only use what I sow myself so that I will have the varieties I covet most and the earliest fruitset possible, but I suppose if you plant late and didn't have time to sow early in the Spring it is a great free gift.