Okay, so I emailed the contractor! I spent a long time working on the email, outlining (concisely) that I was really interested in this stuff but had limited experience and what I had done to try to gain some experience. He emailed me back and honestly, I was too nervous to look at his email for a couple of hours. However, when I finally worked up my nerve, he had emailed me: "This is an intriguing development. I can discuss with my partner and see if we can integrate you in some capacity." Phew!
We exchanged a couple more emails about my interests, if I'd be okay with it being not a regular schedule (which I'm very okay with) and... I'm in! Looks like I'll be working on carpentry, plastering, rough framing (no finishing stuff until I have more experience), even some plumbing and electrical! Optimism + writing skills FTW!