Aww red eyed piggies! My favourite! I don't know why people are so prejudice about them. If it was up to me I'd adopt every red eyed piggie. I only have one current red eyed boy at the moment but his eyes are dazzling! <3
As for advice I'd recommend a CC cage for them if you only have a tiny pet store cage. You can make these in any shape and size you want.
Your piggies will definitely be nervous so don't handle them for the first 2 days or so so they can get used to being in the new enviroment. Whenever you are in the room, talk around them so they get used to your voice and aren't as scared. Try to offer them vegetables through the cage bars. They will be extremely nervous and timid but keep up with it and when they take them from your hand you will feel amazing.
Pellets, try not to get a muesli mix but something that is like science selective or burgess excel or don't give them any pellets at all.
Feed veg twice a day. Their diet mostly consists of hay, around 80-90%.
Guinea pigs are very terrified when it comes to being picked up as its the predator/prey experience but they either will get used to it or you can think of other ways to help with handling. Some people urge them into something and then pick them up that way.
Guinea pigs are amazingly fun when you get them to trust you and watching them interactive with their cage mates is very enjoyable to watch.
Enjoy your two new piggles!