By the nature of your question, I'm not sure you "understand all the plumbing".

One of the Biggest of Big Red Flags in buying a DIY remuddled home is a bath project where the homeowner did their own plumbing. Plumbing codes originate in the health codes. Which is why you need to hire an actual licensed professional to pull the permit and do the work.

I, too, fear you don't understand the plumbing. I think you have more reading to do on the topic.

Perhaps youll get lucky and create A custom vent in the process.

Thank you all for your generous and kind help!

Are you thinking of the over flow that is on sinks and bathtubs? That's different from venting. All drains and toilets have to be vented to air so that the water will move freely. There are plumbing codes that dictate how that venting is done. I would advise you employ a professional for all electrical and plumbing.