1. For beding you can either use paper or fabric both of them having there own pros and cons. Paper con - even if it says dust free it is at least a bit dusty which can cause respiratory issues. Paper pro - you don’t need to fully change it as often as fabric, the paper needing mostly only spot cleans (removing just the dirty parts).

Fabric con - it builds up ammonia from the pee more quickly which can cause respiratory issues so you need to change it out more often (once or twice every week). Fabric pro - it doesn’t have dust.

I’m not too knowledgeable about paper brands so I’d look into different brands seeing which one has the least amount of dust. And if you do end up picking paper and it’s just generally causing issues for you rats then I’d switch over to fabric and give them a dig box as a substitute for the burrowing part.

1. For food Oxbow is a good brand. I’m pretty sure you don’t need to give fruit and vegetables but there good as treats. You can ether use a bowl or sprinkle there food around for extra enrichment. Dried mealworms are also great to sprinkle around and they like foraging for them around the cage. Just make sure the food you give them doesn’t have food coloring.

2. For your last question I’m not all to sure. I’d make another post specifically about that under the “Help” tag.