Like is it generally frowned upon if you get too close to enemy spawn because it is spawn camping?
Yes.
Should you call hits if your own team shot you?
Yes.
Does ricochet count as hits?
No.
How do you execute a knife kill, and does it only count if the enemy hasn't noticed you and if you do it , or can you engage a enemy around a corner and try to land a stab as they try to shoot you or is this not allowed?
Depends on the site but it's usually a light tap to the t-shirt area, with a suitable larp safe melee weapon.
It counts if you manage to do it and you're not dead when you do it.
Trying to stab someone with a larp weapon around a corner could be viewed as blind firing. Most larp safe knives are still "pointy" to a degree, thrusting it wildly round a corner, hoping for a melee kill is pretty dangerous. You could knock off eye pro, jab someone in the ear, who knows what?
I wouldn't recommend it.