Hmm, fair enough. Melting snow into water makes sense - as would treating liquid water in puddles (which a stone of ice melts into) as water instead of merely a contaminant (could be expanded to general liquids; dwarfs could then try to drink blood, mud, or whatever else was on the ground with the proper tags); living off trees and grass could be an alternative to hunting for vermin (which dwarfs currently do if they're starving). Murder/cannibalism also makes sense, especially if tied to relationships (dwarfs would be more willing to eat someone they disliked or didn't know, if they're starving, while they would wait longer to eat a friend or simply starve to death if presented with a lover). Religion could also be tied in, and dwarfs who had to resort to cannibalism once would be much more willing to do so later (or as a fortress-wide thing; once it happens a few times, it's a lot easier to make it happen again).
The downside (upside?) is that, inevitably, someone would try to make a fortress which survives entirely off eating immigrant waves - a bunch of starving dwarfs inside, and a room filled with weapon traps and a designated meating area (typo intended). It wouldn't be a pleasant life, unless whoever was running the fort figured out how to make the dwarfs cook the corpses (mmm, +dwarf meat roasts+), but it would work.