The main questions are:
1. Can I:
A. use a 3x3x3x3 wye with a toilet/WC on one side and a tub/shower combo on the other. I understand that the toilet should be the furthest from the vent to reduce syphon issues but can it be tied at the furthest point? OR, If I cannot do the 3x3x3x3 Wye, I would plan to...
B. pull up more subfloor and have the wye + 1/8 street last for the WC and then another wye for the tub/shower next in line closer to the vent. Room is tight and less floor to remove so I’d prefer route A.
2. Will the wet vent function properly with plumbing designed for my toilet, tub/shower, floor drain and Lav (double faucet, single drain).
3. is the existing vertical 1.5” vent large enough for washer, wc, lav, tub, floor drain?
4. AAV’s are okay where I live, should I add one to my lav just in case?
5. for lav and washer, can a sharp 90 be used from vertical to horizontal transition?
I have included a couple drawings / pics of our project. Thank you for your help!