Hey I just got too piggies. My mom is the same and there hutch is outside which is not ideal but that happens sometimes. I keep mine in the corner of the garden with all areas around them wither wall or trees, this breaks the wind a little bit so shouldn't get too cold. Also they need a little bit more food than indoor piggies to keep them warmer. I also have lots of hiding toys for them which they either both snuggle in or they snuggle into their bedding. Also I don't know if this is common practise but when I bring them in I have windows open so they don't go from hot and cold all the time. An issue with being outside is bonding apparently takes longer, but I only had my piggies over a week and Barnie is happy to let me stroke him when his eating and will even fully relax and lie down all spread out, scooby either runs or freezes when I go to stroke him so just needs a little more time, but I just sat outside their hutch talking to them, before Barnie let me start stroking him I just put my hand on their level in their cage then when they had sniffed me out I giggled my fingers and slowly moved my hand until they got used to it moving near them then try stroking them. So as long as you take time out to let your piggies accept and trust you and also provide them with extra bedding, food and shelter they should be ok.
And I wouldn't get three, one reason, which is selfish a bit but I love getting to know my piggies and anymore than two I think would be difficult if like me these are your first.
Best of luck
Amy xx