Ahh guinea-pigs 
Lots of owners keep them indoors. You need to be careful where you place them . No overheating, draughts,full sun or damp.
Yes, they'll eat wires !
Mine have (not the ones I have now, we have too many wires to free range) in the past eaten: carpet, shoe laces, any paper, house plants, books, onion skin........
And we had one that could run upstairs (tiny tiny little homebred female) and two that could climb downstairs.
You'd be safer getting an indoor run , if they go outdoors you can get a secure covered run.
Piggies don;t smell if they're kept clean, males smell a bit 'boary'. Hay smells more than the pigs.
They are crepuscular (active dawn/dusk) ours sometimes delight in being noisy at 3am in Winter, we put a duvet over the cage to insulate them. I tell them "Oi Pigs, shoosh" they usually whinge if they've run out of food.
So you could close the door and they'll get into the routine of Night=Sleep. (Until someone opens the fridge or rustles a crisp bag.....)
GP2 clanged his plate against the bars at 6am to tell us to feed him.
Insurance-I got a quote for GP1/GP2 but it was £££.
You're best to put money aside, you might never need to spend it. They don't need vaccines or neutered (unless you want to mix a boar with sows).
Things like teeth you could find the price of to give you an idea.
All mine are from Rescue, they do tend to have more boars. We were lucky that when we needed two sows they had a huge number of sows from a group of ex breeders. Feisty, needed handling and some TLC.
When we got our new girls, there was nothing (I did look at Gumtree but I wasn't going to pay the owner to do them a favour for their Desperately need to rehome due to allergies I want £40 adverts . Their loss, I'd have loved their Piggies but I wasn't going to put ££ in their pocket).
Then two ladies were a-waiting and they now live with us (they refuse to bond with our lardy trio so we have a 3+2 set up)
Phone a few Rescues, I reckon now the Schools have gone back their will be a few "Kids lost interest" ones.

Tiny piglets are lovely but they are very skittery and quick. They soon mellow to lardy adults.
All my piggies are lovely, I have one who is a bit bitey (when she's in one of her moods) they get a bit snipey in season but the temper lasts 24 hours.