Hey, i'm living in Singer this year but moving out soon. First i just want to say, i completely loved my time in singer, it's such a great place to live in my experience! There was such a good atmosphere and i loved living so close to all my friends, i'm really going to miss it next year when we're all in houses. It's so relaxed living there, compared to some other accoms where you can't bring friends around without signing them past security and the like. As for the questions:
1) I can't say i know for sure, but in general singer are pretty relaxed about most things, i can't see it being a problem. Even if you did bring one, you could easily hide it in the wardrobe during inspection week. We only ever had one flat inspection in my time in singer and we were told when it would be so we could prepare.
2) There's a combination of wired and wireless internet, it's a bit slow but fairly reliable. There has only been a few occasions of it going down, and it's usually repaired pretty soon.
3)I can't say i've had anything stolen at all while in cov. The flats are really safe, all the downstairs windows have bars on to prevent people breaking in, the main front doors and the flat doors can only be opened with a key card and your bedroom is locked with a key so it'd be pretty hard for anyone to get in. As for flatmates, it just so happened that i got a really like minded bunch of flatmates, and we all left each others stuff alone. No milk/cheese/butter theft in my flat. I do know some flats where they had kind of an open kitchen policy, in that they would all share groceries and utensils and stuff and that worked for them.
Enjoy your time in singer, if you aren't from a city (like i wasn't) then it might seem a little daunting when you first move in. It's near a bit of a dodgy area called Hillfields which really scared me when i first got there. But after a while, you'll feel right at home. Have a great first year
edit: Just seen how old this post is, my bad! But hope the information helps anyone moving in this year haha