Remodel drain question

We are doing a bathroom remodel and are removing an existing wall-mount toilet and replacing with a standard floor-mount toilet. Unfortunately, this creates a potential problem with the drain, since its now running in a different floor joist bay. There is a small stub wall next to the toilet separating it from an adjacent tub/shower. The tub/shower drain vent is located in this wall between the tub/toilet. The main drain line is on the other side of the tub:

Toilet, wall with 2" vent, tub/shower, then main 3" drain line.

The prior wall-mount toilet used to have it's own dedicated vent and connected separately downstream to the 3" drain.

My question: Can I run the new 3" ABS drain towards the drain, pick up the 2" vent in the stub wall, then use this as a wet vent to pick up the tub/shower drain before draining into the main 3" drain? Based on the code I have read, it looks like you are allowed to use a wet vent for single bathroom groups, but the toilet is supposed to be downstream of any other fixtures, whereas in my case it would be upstream. Is this really a problem?

Thanks

You will probably get more input if you post a drawing of the existing drainage plumbing along with a drawing of what you propose to do.

Where the vent is located determines whether it will work or not, NOT whether the toilet is upstream or downstream.

Additional info

Toilet flange is located about 18" to the left of the 2" vent. Tub/shower drain is about 12" to the right of the same vent - so the vent is in between the toilet and tub drain. Its about 4 feet from that point to the main 3" drain.

I don't have the ability to upload a picture, but in order of connection:

3" toilet flange, 3" long sweep 90, 18" 3" pipe, 3x3x2" sanitary tee for the 2" vent coming off the top, 12" of 3" ABS, 3x3x2" sanitary tee (2" tub drain coming into the top), then about 4' straight run to the main pre-existing drain.

One other question would be - should I use a 45 wye instead of a sanitary tee for the tub drain connection to the 3"?

Thanks

quote; 3x3x2" sanitary tee (2" tub drain coming into the top),

1. "Coming into the top" makes it an "S" trap which is ILLEGAL regardless of the fitting you use.
2. You need a "Y" or combo for the vent connection.
3. The tub has to connect to the vent riser pipe, NOT the main line.