New shower drain meets 3" drain and distance from existing vent

I'm adding a 2" shower drain to an existing 3" drain and I've the following questions:

1) There's a 3" vertical vent 6' upstream from where I plan on connecting a shower only (no tub) drain to the 3" drain. Is the vent location going to be an issue?

2) The shower drain is in the same floor joist cavity as the 3" drain it needs to connect to and mercifully it's offset enough for the p-trap to sit comfortably next to the 3" drain. The trap exit can be up to several inches above the 3" drain if needed but not sure if there's a rule of thumb there.

What I plan on doing is inserting a 3"x3"x2" wye about 2' downstream from the p-trap and using an assortment of 22.5 degree elbows to get the waste water into the 3" drain from the trap exit. Is there a minimum or maximum distance between the p-trap exit and where the downward connectors funnel the water into the 3" drain? I feel like if that distance is too short I'll get close to an S trap situation.

Thanks!

Venting is tricky, and varies by state. Most of the information you’re asking about will be in your local plumbing code. The minimum length of the trap arm to avoid forming an s trap will be in the code as will the minimum and maximum distances of the individual vent(if required). The height of the weir of the trap in relation to the 3” line will be determined by the length of the trap arm and minimum pitch of the size of pipe you are running. Depending on what branch interval the proposed shower is on will determine whether it needs to be individually vented or it can be stack vented. There’s a lot to consider. You may think about asking whether there are any local plumbers willing to do the rough plumbing only. (I wouldn’t, but some people may be willing to). Another consideration is if the domestic supply piping is adequately sized to support an additional shower. Some pictures would help, but again, local codes do vary so I probably won’t give any specifics.