Могут ли новые пользователи, отвечающие только по электронной почте, получить повышение до более высоких уровней?

I will have around 700 users imported from my Mailman server who will have accounts on the discourse server once it is opened. They’ll be at level 1 and preassigned to one of two groups.

I’ve currently got the site set so that starting new topics by email is only available for level 2 or higher.
But will users who only reply by email be able to earn promotion to level 2? Do I need to tweak the settings for what it takes to earn promotion? (It isn’t clear from the documentation if they need to meet ALL of those conditions or just one of them.)

It is “all”. So you may need to adjust (or find some alternate way to promote).

If they read only via email then they will have zero read time.

OK, I’ll have to figure out a different plan.