I just finished my basement brewery. You can check it out here.
First, I'd say you need to decide whether you want to mount heating elements in your brew pots or make heat sticks. Heat sticks are definitely more flexible. You can move them around from HLT to BK and even stir your mash with it if your temp is a bit low.
Once you get the hang of building heat sticks, they're pretty easy to build and to use. That being said, you will need two 20 amp lines. I don't think one 30 amp 240 outlet will help you when it comes to having two heat stick lines, though someone with more electrical experience may be able to explain how to make this work. I'm thinking it may be possible to run one leg of each line to a gfci to make two breakers capable of 15 amps each, with one leg as a traveler wire. But I'm not sure.
Two 2000 watt heat sticks should be enough to boil 5 gallons. Two 1500 watt heat sticks may be enough for this as well. I would create two boxes, each with a gfci and a switch controlling it. This way you can easily turn each heat stick on or off with the switches.
For ventilation, I think most have said that a bathroom exhaust fan may not be enough for your needs. You can try it, but most have said that at least 300 CFM is need. Most dryer vents are made with 4" vent lines. Looks to me like that maximum inline fan at 4" is about 165CFM. Kind of low on the scale. I went with 745CFM for mine and it definitely clears all moisture. There may be some kind of squirrel cage fan you can rig up that will move more air.
Another idea was suggested by Bobby from New Jersey when I was planning my set up. You rig up up your vent fan to a lid that can sit an inch or two above your pot. At such a close proximity, your need for more CFM drastically decreases. Maybe worth a shot in your situation.
You might also consider rigging up a cap of some kind with a hose connect for a waste port. I did this in my setup. Using quick connects I can easily pump out from my hoses, keggles, CFC, and pump. No mess at all, straight into the waste port.
It can be done, especially if you don't mind checking your panel and running a few 20 amp lines with gfci receptacles.
Maybe someone with more experience wiring up a 240v line can weigh in on how best to use that. My understanding is that they don't make 240v gfci receptacles, so you'd need a spa panel or a 240v gfci breaker. I don't know if anyone uses a 240 heat stick, but it's another option.
I hope that helps you get started. Good luck with your build. I recently finished mine and really enjoyed brewing with it. Indoor electric brewing is great, especially if it's 40 below out. Least your chiller should work great at those temps.