Is this plumbing setup ok?

Hello all,

I am new here and have questions about the setup in the attached picture. Can you please let me know if it is acceptable or what changes need to take place for it to be acceptable?

a. bathtub, sink, vent line, and shower all on the same plane – directly under floor joist, they would all be angled 1/4" per foot
b. above mentioned lines are ~30†above dirt ground
c. 3†main line on ground (this line has not been touched/moved)
d. short 3†line angled upwards, so the toilet drains correctly (this line has not been touched/moved)
e. all fixtures/drain lines to the right of this drawing not touched/moved at all

1. can this vent line be used. It is dry until it would hit #1
It is 1 ½†going thru roof, which I can’t change. Would 1 1/2" for rest of vent be acceptable?
2. to connect bathtub line to vent line at #1, what is used
3. what size line should be used from #1 to #2 (red dotted line)
4. to connect above #3 (red dotted line) to shower line at #2, what is used
5. what is used to connect curved red dotted line (at end of shower line) to 3†line. this line would drop ~22" to attach to angled 3" line
6. how do you add the sink into all this
7. is it correct to have water drain lines behind toilet

Thank you for any guidance you can give me.

I can't make much sense of your drawing, and judging by the lack of responses, I don't think it's just me.

I recommend you draw an isometric plumbing diagram of what you are doing, and then it will be much easier for us to help.

You are trying to learn in one email what it takes plumbers a lot of time in school to learn how to do it right.

For starters,. the vent cannont be horizontal ( less than 45º) until 42" above floor.

I got a headache trying to figgure the drawing out. Jimbo has a piece of it though.