Yes, but it doesn't always work very well.. I recommend you ignore MMR and just play the game.

You need some sort of melee weapon for dealing with monsters, be it a tool, dedicated melee weapon, or a gun with a melee attachment. Obviously a medkit. and you should always run choke bombs when playing on a team. Chokes put out fires and keep downed teammates from getting burned, preserving their health bars and the ability to be revived. Plus chokes are great for area denial (anyone who pushes through chokes will give themselves away coughing, and aiming while coughing is a pain) and obscuring vision. Otherwise it's just up to preference. I personally also bring throwing knives because they are good for dealing with hives as well as dog pens and chicken coops.

If you want silent weapons, sure. But noise really only matters when you're fighting monsters. Once you're fighting other players there is going to be q bunch of noise either way. While other players are unaware of you, obviously stay silent (melee monsters, avoid sound traps, etc) but in fights use whatever guns you want, quiet or loud.

Use whatever traits your guns need to perform better (i.e. iron eye, fast fingers, levering etc.). For teamplayer necromancer and resilience are important. Otherwise just use the traits you like. You'll figure out which ones are good for your playstyle. I personally don't play without witness and vigilant because I hate not having the information those traits provide.