Drain and vent layout help

[Brian Smith]

I am trying to help my brother out with his bath remodel and wanted advice on this drain/vent diagram.

purple are 3" or 4"
red is 2"
blue is 1.5"
light blue circle is 2" vent
orange circle is main 4" cast iron stack in basement
(note he flipped both tubs for showers with left drain in BATH, and right drain in Master Bath)

I am concerned there is not enough venting for the toilets. 14 will vent master vanity good i think, as will 11 vent bath vanity and bath shower. 18 will vent master shower and also go up to attic pick up the vents 11 and 14 and go to 3" in attic before exiting through roof (4 that main stack will go straight up for about 6 inches above the connection into the new purple pipe and drop from 4" to 2" to drain shower / wet vent main stack.)

Any help would be appreciate, my mom is moving in with him so the 2nd bathroom as needed, this is a case of loving my mom so trying to help him complete this is time (had a plumber hired but didnt show at agreed upon time so now in order to get done in time we have to do this ourselves.

 

[Brian Smith]

I might be able to do this instead not sure will check tomorrow

instead of having 5 come off the 4" and run in to the wall for venting at 14 then over to 15 to drain master vanity, perhaps extend the main 4" drain pipe to the bath/hallway wall, drop down to a 3" and go vertical, off that vent takeoff 1.5" to drain the master vanity and vent through the 14 vent

 

[Sponsor]

 

[Brian Smith]

I know its not the typical diagram I just couldnt figure out how to do that. Can anyone give me advice on this, I have to install this weekend because my mom moves in less than 2 weeks and our plumber after taking the job said it would be 3 weeks to come out and we can not find another in time. I have done basement bathrooms before but this is a bigger project and I just want some advice that I have enough venting and in the correct locatuins.