New Piggie Dad Here!

Okay so I have been wanting guinea pigs for a long time and I found one at a flea market in the early spring. She was not well taken care (kept in a 10 gallon fish tank and fed what looked to be hamster food) of and she died after a few days of me trying to nurse her back to health. I was heartbroken but I did report the guy that sold her. I have been trying to save up to buy a pair or a trio of Peruvian girls but I eventually gave up on that since the breeder I wanted was way to far away. Anyways I was in Petsmart tonight to get cat food and I always go and talk to their baby boy piggies. Tonight in the spot they normally keep chinchillas they had 2 ADULT male piggies with no price sign and a hand written sign that said "Adopt Me!" "Ask a sales associate for more information". So I asked and the manager told me that someone brought them in for a return but when they were told that the warranty is up and they couldn't get their money back they just left them sitting next to the fish tanks and drove away. The manager pointed out that I am always talking to their guinea pigs and I should adopt them. She said since I frequent the store she would waive any sort of adoption fee. So I filled out the paper work and took them home. They are two boys of unknown age but they are very attached to each other. The gentlemen with the short hair is more than willing to take some greens from me and is not quite as skittish. The lad with the funny haircut is a bit scared and would rather hide behind his brave brother and observe. They ate the fresh stuff I gave them and now they are being left alone in their cage for a while. I have them in a rabbit exercise pen lined with a fleece blanket with towels underneath for now. The pen is a little more than 2.5 grids long and a little more than 2.5 grids wide. Do you think that is big enough for them? I really don't have enough room for anything larger and this pen offers a door big enough that I can fit myself through it to interact without towering above them plus the bar spacing is small enough that I don't have to worry about kitty paws swiping at them. The best part is there is a removable door that can lead to another playpen or a cage. I have no idea where I found this playpen but it was meant for a rabbit or a ferret. I would rather put the coroplast underneath the pen and I will put a removable lid on it somehow too. Here are my new boys: