It depends on what bedding you use. If you use fleece (washed three-six times before first use, wash generally without softener and with non bio on thirty usually. Use puppy pads, towels etc under fleece which need replacing/washing every few days depending) you spot clean 2-3 times a day and swap fleece for fresh one every 2-5 days. Woodshavings every once or twice a week, spot clean once a day usually. There are other beddings like vetbed etc too
You should clip the nails before they have the chance to curl. I usually cut whenever I feel the bit after the quick looks a bit longer than usual. It's best to let a vet show you how to cut nails before attempting yourself.
Piggies eat pellets, hay and veg/fruit. Hay is the main part of the diet and must be there at all times as piggies constantly eat hay to keep their system moving and keep weight up etc as they are small and burn fat easier. It's incredibly important.
Veg needs to be fed daily as piggies, like us, cannot produce vitamin c. I'll try to find info on different types to feed, but one food they can't eat iceberg lettuce at all. Coconut is quite high in fat so don't recommend it. Parsley shouldn't be fed too often, once a week at most. Coriander can be fed more, two or so single strands a day I think. Romaine lettuce is ok, I feed it every day to every two days, one leaf to a pig. Kale only once a week. Bell pepper daily, people I've seen prefer red more than greed as I think red is a bit sugary but green can encourage bloat.
I feed half a handful (to each pig) of Burgess Excel Mint everyday. It isn't as important as but is good so good idea to take note of pellet feeding
to the forum !
I currently have two girls in quarantine and a boy. Are you getting two boys, two girls etc ? Cage size can depend on gender due to a lot of boars needing space and territory. The dog playpen size sounds a bit small in general, possibly. My mind isn't with it today lol, sorry 
Yes, it's a nice size for two girls 
