They do look to have some Flemish Giant in them as others have mentioned. Domestic rabbits cannot have offspring with wild cotton tails as they are a different species (they come from the European rabbit).
As you've seen, rabbits reproduce quickly and can hide pregnancy well. They can become pregnant again immediately after giving birth, at as young as four months for some. So it's important to confirm their sex and separate them early on at around three months of age.
Rabbits can be fixed at six months, which will not only prevent more pregnancy but it can help with many things such as litter training, spraying, humping, aggression, and other territorial behaviors. Rabbits often go through a personality change at 4-6 months because of their hormones, so it's common to see the behaviors above until they eventually outgrow it or are fixed. Fixing your rabbits also prevents health issues such as uterine cancer, which is very common for does.
Rabbits as adults can often be hard to house together, but fixing them makes it easier to bond a pair as well.
As for care, adult rabbits should be on a diet of ¼ cups timothy pellets daily, fresh spring mix veggies daily, and unlimited timothy hay. I recommend the Oxbow brand. Avoid any food or treats with seeds or dyes. For treats, they often like bananas, apples, carrots, and herbs.
Rabbits under six months and pregnant does should have unlimited alfalfa hay and pellets.
I recommend using water dishes rather than bottles, since rabbits do need a lot of water and water bottles make it difficult to get a sufficient amount from. They are also difficult to clean, which can leaf to bacteria growing in the nozzle. Ceramic bowls aren't as easy to knock over as others, and you can buy some with stands to keep hay and things out of their water, though it should be changed daily.
Housing rabbits is often a controversial subject. Many people keep their rabbits outside in wire cages or hutches. Pet owners tend to prefer keeping them indoors for many reasons.
Rabbits have many predators outdoors, and can go into shock from simply being spooked by one. Heat is also a concern. While rabbits can tolerate the cold well, high temperatures can sometimes cause heat stroke.
And most hutches and cages do not provide the space that rabbits need to exercise and play.
When housed indoors, rabbits can free roam like a dog or cat if you bunny proof and litter train. For when you cannot supervise your rabbits, wire dog playpens can make great enclosures indoors. They're cheaper than cages and provide more (much needed) space for your rabbit and its needs. A rabbit enclosure should include a large (cat sized) litter box with pine pellets (avoid cat litter) and plenty of fresh hay, multiple hiding options, toys to keep the rabbits entertained and their teeth down (this prevents chewing other things), a mat or rug to protect your floors/carpet and to provide traction, and food and water of course.
Taking on this many rabbits is a lot, so if needed there are rabbit rescues that can take some or all, and they may help with getting them fixed for you.
The house rabbit society has a list of reputable rabbit rescues.
I hope this information helps you and your new bunnies, they're very lucky that you're willing to help them. Let me know if you have any questions
sorry for the loss.
