Hi. Do you know what code you're trying to meet? it might change the answers. I'm, not a plumber, just DIYer, but here's what I see:
- You might need a clean-out on the line from the second floor bath based on the directional change. Ask the AHJ.
- It looks like you have a sealed sump pit. you might want to plumb in a vent for it to avoid straining the seal when it operates.
- Vents should be rolled at 45 degrees from the horizontal and stay at least that pitch until they're above the spill line of all the served fixtures (i.e. can't go horizontal till around 42" up). If you can get them near the walls, you can "cheat" normal clearances with gaps behind tubs, notching the bottom plates of your 2x walls, etc.
I'm dealing with similar questions in my basement remodel and have found that keeping the drain lines near usable wall cavities makes getting proper venting in place MUCH easier. Do you have any planned partition walls that you can leverage to get your vents up and over?
Dan