Hi crocodile guinea-pigs are fabulous little animals but as you say there's alot to consider.
You want two (at least) there will be bonded pairs or there might be a sow trio or a neutered boar + sow/sows.
Don't go for a boar trio unless you are pig savvy.
At the moment I have a 1yo boar (who was cagemate to our older boy until he died) . The 1yo has been neutered (not sterile for another 2 weeks) but he's side-by-siding with two rescue sows.
They're in a 4'x2' cage in his Pighouse (Pighouse is a 6'x6' wooden Playhouse adapted for Pig Living )
The cage seems big enough but Hand on Heart , it isn't. They have a 7'x4' run (he's in his own smaller run) so it's a temporary accomodation till they can all be together.
Ask them the history of the piggies. Our first boars were in Rescue (accidental litter) and were lovely, cuddly. Had the odd scrap but nothing we couldn't sort.
GP3 was a Rescue (breeder "didn't really like guinea-pigs" ) he was a tiny piglet to match up with GP1.
We didn't want to put GP3 with a tiny boar (je'd bonk it) so I got two feisty sows - and they are feisty.
I don't think anyone looking at a first pig would want my tiny little sow
but I'm in it for the long haul and I'm winning her over .
Both my new girls had been taken to Rescue pregnant and rehomed once their babies were weaned.
So - they can be in Rescue for many reasons that are no fault of their own.
Let them know if you are a novice, they'll help you out.
They get used to a routine - breakfast, dinner, cuddles, run time. They rely on it.
We have ours in the Pighouse (It has removeable windows which are re-inforced inside against foxes and flies)
In winter they come in at night and I heat the Pighouse for day (either SnugglePads or a small heater + loys of hay)
They love to scramble through hay and ferret about 
We have a fox problem too, but actually, I haven't seen them of late. Hopefully they've moved on, but I doubt it.
Bedding - I use bewspaper and hay )on top of cardboard and rubber mats that they can;t chew)
Puppy pads ( can't get to) under the paper.
Sawdust and shavings can cause respiratory problems, shavings are drying on their feet and coats.
Good Luck.
Happy Reading 