Epitech student here (42 is kind of a fork, the whole managing team is Epitech Alumni). So far they copied everything from Epitech and it seems to work in the same way so:

1) Mentors should be available at 2 in the morning. Not that they have to (most of the time) it's just that you mostly interact with teaching assistants that still are in school working on their projects too, so they usually pull the same kind of hours than you.

2) You have really tight deadlines and a huge amount of project so it's not unusual to have to work 15 hours. But the whole thing is just about learning to manage crazy constraints, you deal with it the way you want. If you choose to work 15hours a day an manage to be efficient then great, but it's more about learning to be organize / be efficient.

I feel like there are so many other places to find mentors now that it's not necessary to have them at the school itself.

As for the second issue, I stare at a computer screen for at least 12 hours a day - you have to be careful about it (backlighting, fl.ux, etc) but it's possible to do and can result in some incredibly productive days. That said, 15 hours is a long time.

Maybe. For general programming questions like how to loop two things at the same time or combining two lists into a dict, yeah. For particular open source project if you are lucky yeah you can get help from IRC (or fall back down to reading source code). But infrastructure, scaling, security, these are very specialized areas. You can get a general idea from stackoverflow or security exchange but implementation wise SO is not a good place to find inspiration.

In the past when I had to deal with puppet/chef I constantly had problems that the mailing list just couldn't help and the only way I could get help was to bring someone in and had them debug in real time with me.

Used to do 15 hour days.. then cubital tunnel :( Now I'm trying to recover and limiting myself to 4hrs.