Hay bedding on top of newspaper works well, and they love it because they can burrow in it and eat it. It can be quite expensive, although there's plenty of places to buy it quite cheaply.
I used to use shredded paper and it's certainly cost-effective, but needs cleaning out quite often and isn't the best for piggies.
Other bedding ideas you could investigate:
https://www.theguineapigforum.co.uk/threads/types-of-bedding-reviews-and-tips.53208/
A photo of your setup would be really helpful if you could post one
I'm sure you know that guinea pigs need a constant supply of hay, so any toys that involve hay usually go down pretty well! Examples include toilet rolls stuffed with hay and hung up with string, or shoeboxes with holes cut in that they have to pull the hay through. Or just shoeboxes full of hay they can sit in. Treat dispenser balls are quite popular too, I think but are better for using in a run than in a hutch.
For more ideas on toys, this thread is very helpful:
https://www.theguineapigforum.co.uk/threads/guinea-pig-toys.43520/
Guinea pigs can't be toilet trained
as such... The way it works is that you work out where they poo the most, and then put a littler tray in that place. Since they're creatures of habit, they'll keep pooing in that corner, but now in a litter tray that is ten times easier for you to clean out
If you haven't got a run already, they'll definitely appreciate one, but it's important you get your pigs ready to go out, since their digestive systems are quite sensitive to anything new.
This thread should help:
https://www.theguineapigforum.co.uk...-preparing-your-piggies-for-lawn-time.111794/
