Why return? I bet you can find a lot of volunteers for a one way mission, especially if you offer to follow them with supply trains every year or so.

Even if this is possible, it'll probably be prohibitively expensive to do constant resupplies when you won't know for years if previous trips have worked. A manned mission or a resupply mission would also be orders of magnitude beyond the masses they're talking about, which strains credibility even further.

I am pretty sure you just sent out a new boat of supplies every year make it or not. Worse case the mission fails and the next mission has 20 supply ships in orbit waiting for them. I have no idea on the minimum mass required to send supplies, i.e. if you can recycle 99% of the water you need, would only need a few drops per day. If you can only recycle 50%, you are going to need a bunch.

Nah - they're already pushing some theoretical limits by talking about planetary levels of energy. You're talking about just throwing money at doing that many times in a row with no proof of success.