There was no individualistic mentality. To be communist, to be Soviet, you were not an individual at all but rather a piece of a larger picture and that larger picture was the concern--not individual woes/needs/wants.
I would like to highlight two passages from their diaries:
This is from Yudin talking about the workers at the camp they stayed at:
"Read everything that they can get their hands on and do they sing ... Quietly, from the heart. The songs are old, long forgotten or never heard. Here they are ... It's so good!
Why don't we sing such good, already forgotten songs. And in general, we don't sing about the soul in places where there are some outsiders, it's not singing, not soulful, loud."
He seemed to be really fond of these songs.
This one is from the group diary, this entry written by Doroshenko:
"The boys started copying some songs. One man sang beautifully. We heard a number of illegal prison songs (Article 58 counter-revolutionary crimes)."
While he says the singing was beautiful, he also highlights these songs are illegal.
Everyone else's diary talks of the songs fondly. This I think points to certain levels of individualism and also, not most of them not being very "soviet". Or perhaps they just didn't know the songs were illegal.
These students, although accustomed already in their short lives to hard work, being poor,
Some of them were in fact from upper middle-class families in Yekaterinburg, and one of them had a very well paid job in Moscow.
I don't disagree with the gist of what you write though.