First off, welcome to GPC! It's wonderful that you found this amazing website BEFORE getting your pigs, and have been doing your research! To me, that means that you really want to give them the best life possible! You will find loads of information on this website, which I realize can be overwhelming. If you cannot find an answer to a question you have about guinea pig care, please ask! Members here would be very happy to answer your question and help you out! You look like you are well on your way to becoming a good piggy parent! I am also SO glad that you are adopting! There are so many homeless guinea pigs out there in need of homes, and it usually takes people quite a while to realize that humane societies and shelters HAVE guinea pigs (I know I didn't realize until I had 3 guinea pigs already!).
If you haven't already seen the charts created by Ly (which she spent LOTS of time making) please check them out! Here is a link to them:
https://www.guineapigcages.com/foru...-charts-poisonous-plants-list.html#post254730
It shows what vegetables and fruits guinea pigs can have, in what quantities, and how often!
Also, I'm blanking on what kind of loose bedding you are using. I've had guinea pigs for 1.5 years now, and being a college student I know how quickly loose bedding adds up with these guys (they are basically very efficient pooping machines!), so if you haven't looked into fleece, you might consider doing that! Here is a link on how it is used, prepared, etc.:
https://www.guineapigcages.com/forum/bedding/21568-fleece-project-study.html
It's just something to consider.
Now, I must also admit that those hay balls can be dangerous, I know from first hand experience.
This picture was taken a few weeks to a month into having pigs, and I was still learning about them. My smallest girl, Skunk, was eager to get inside to finish off the hay, she somehow opened it up and crawled inside. She wasn't in long, and I removed her carefully, but have NOT used the hay ball since.