Caveat - I am not a plumber - I think the general venting scheme may be acceptable, considering the relatively short distances. However, is that capped 3" pipe where the toilet used to be, or am I missing the toilet drain in the pictures?

The angles for many of the pipe connections look like they could be a problem. For example, for a 3" toilet drain pipe you want gradual bends (45 degrees, etc.), especially when its close to other drain connections that would be plugged if it went the wrong way.

I think I would want the sink drain to enter into the top half of the 3" pipe, like you would if it was a dry vent. This keeps the connection up high where it is unlikely to be blocked. Wet vents are normally kept open by flowing water, but with that close toilet connection I would be concerned that sewage could backup the wrong way and block the sink drain/vent.

Bruce

2nd picture, where does the pipe at the top of the picture go? Also, the sanitary tee is upside down.

Not really a fan of a 2 inch pipe wet venting anything. I would like to see 3 inch pipe at the vent/vanity transition. Technically it is ok, they say 4 fixtures can be wet vented with 2 inch. Unless you are draining a sink on the vanity and taking up all the space in the pipe while taking a shower downstairs. The shower may not drain well while the sink is draining.

Don't believe 1 1/2 pipe is an adequate enough for venting also the distance of your toilet from the vent pipe might also be a problem .

I see three major problems. The two inch has a sanitary tee laying on its side which is illegal. A san tee can only be used in the vertical position. The toilet drain that is capped is also a san tee laying on its side, not legal, where the black pipe connects to the 4" there is a saddle tap. This is not legal either. A 1 1/2" vent is legal. We can not tell how far the shower drain is running but it can only be 8' away from the point of vent measured along the axis of the entire pipe to the weir of the trap. Your point of vent is in the middle of the san tee for either the toilet or the shower.

That is all 1960s genova pvc, it was always yellow. genova is still around. I see many issues with the way it was installed. I see a san tee backwards and used on a horizontal run. I also see another tee on its side. all of the lines are running in the wrong direction. Even in the 1960s you could not do it that way.