I have experience with both males and females, and while females are supposed to be easier to bond, I know a pair that bickered for as long as I knew them, and even after months the older one would try to nip at the little one's ears.
It really depends on the piggies.
I would suggest adopting from a rescue a pair that is already together, that way you won't have to wait the 3 weeks to quarantine, you can ask the foster home about their personality, any past medical issues, and learn what they love and how to take care of them quicker than trying to try to get a baby used to you. In my area there are ALWAYS bonded pairs waiting for adoption, and they don't get adopted as quickly because people don't want to separate them.
From my experience with males and females, whenever my friend would babysit my 2 boys he would always remark that they smelled a lot worse than his 2 girls smelled. The girls poops were HALF the size of the boys poops, so they didn't stay wet and smelly for as long, but that may also depend on the piggies, as I've seen males with more girl-sized poops than my boys.
Like everyone is saying, it's a huge responsibility, and it does get tiring after awhile, cleaning the big cages and trying to find time to let them out for floor time, making sure they get veggies every day. I know after about a month or two of having 2 piggies I started to get worn out, because I didn't realize how much work they are.
I know you might feel attacked with all of these people lecturing you, and I know how that feels because I get lectured a lot here too, but it is for the best in the end, we all just care a lot about your piggies
As for cat-proofing, I have a very terretorial cat we found as a stray, so his hunting instincts never really went away. We just keep the piggies in my bedroom (It isn't reccomended, because you need a high traffic room for them, but as long as there are piggies in my room my room always has people in it petting and cuddling the piggies) that way when we aren't home we can shut the door, and when we are home we can heavily supervise the cat. If you are going to have it out in the open, you can use zip-ties and connectors to make a very nice lid for your cage. We used to have a lid, and we cut off the bottom of a connector so that it could just rest on top of the cage instead of clicking into place, and we could open it like it had hinges because of the zip ties. It could safely hold a cat if one were to jump on top.
Coroplast is available at most Home Depots that I'm aware of, and ask your parents if they use it for signs at work, I know in the back of my work right now we have a GIANT piece of coroplast just waiting to be thrown out, I think it was an old sign.
This was a giant post, but I hope somewhere in here I helped.