Thanks to you all for your helpful advice!
I PMed both Mokulele_Hawai'i and tonycoenobita to ask them if they can tell me something about special needs etc. of this species.
@MacandHunter: What a sweet idea to name them "Blueberries"!
So I guess I have six Blueberries, or "Blues"(?), now...
They seem to be doing fine by the way, roaming around in the terrarium. They also seem to be more active during daytime than my PPS, but that could also be due to the jet lag the transport may have caused...
Anyway, they're feeding well on the food I offered them and one has already got himself a new shell!
I'm going to let them destress for another few days, though, before upsetting them again by taking more fotos...
CU,
Dario