I usually go for
2 miners (One of them has record keeper/appraiser/organizer, so he can be both bookkeeper, broker and the manager)
1 carpenter/mason/mechanic/architect
1 stonecrafter/metalcrafter/woodcrafter
1 farmer/brewer
1 blacksmith/armorsmith/weaponsmith/furnace operator/wood burner
1 woodcutter (After he chops down enough trees, like, 400 logs avaliable, i make him a farmer)
I disable hauling for the two miners (I don't want the constantly hauling the heavy rocks they mine), the carpenter/mason (This is very important, because he is going to be making beds, tables, chairs thrones and coffers), the farmers (He needs to focus on farming). You may want to disable hauling to all of them later and, as i said before, create special dwarfs who haul all day. There's going to be the general purpose hauler, who hauls everything, and the furniture hauler, who hauls beds, doors, tables, thrones.
Talking about food, you may want some fisherdwarfs or hunters, i really don't use them, but that's just me, most people use them and, as i've heard, they're a reliable source of food. If you have a river near your fortress, send your fishermen there! Of course, you don't want the river to be too far, because if some hostile creature(s) attacks your fortress, your fishermen will be the first to suffer! Seriously, the Cyclops, Ettins, Minotaurs and Werebulls will murder them, so be careful! Fishermen use their beards to fish and beards can't protect them, but hunters use crossbow, which might come in handy on an attack. Make sure the wildlife around your fortress provides a good source of food. You said you embarked on half of a mountain. I think there are yaks there, which is awesome, yaks are a excellent source of meat.
You might want to slaughter your two caravan animals (They're going to be yaks, mules, camels), which might produce a decent amount of food for your first 7 dorfs.
Farming, you said you have 2-3 farmers, huh? Farming is the most reliable (In my humble opinion) source of food. I have, currently, one thousand-something plump helmet on my fortress, which is result of having a lot of farmers. Farming is also extremly useful to make drinks. Your dwarfs are little alcoholic bearded creatures and they need alcohol to go through the working day, even the kids! I heavily recommend setting your stills as fast as shit (Seriously). A sober dwarf is a unhappy dwarf, they're going to be less productive and less happy.
Also, after a while, they're going to start complaining about drinking the same booze all day. They want more than just dwarven wine! Brew pig tail, cave wheat and sweet pod! Give them ale, beer and rum! I set my farm to make plump helmets one season, and them pig tails/cave wheat/sweet pod on other, with some plump helmets too. This way, there is going to be a wide variety of booze to your dwarfs enjoy.
And, about trading. It's really helpful at the beginning, but, after a while, you might just want to throw those tree-hugging hippies down to the magma! As Smeeprocket said, you can sell trap components, which people often consider an exploit. If you don't want that, just sell some metal crafts. I sell silver ones, as they're worth a decent amount of Dorfbucks and they can afford some seeds, cloths (Later), food and, of course, BOOZE!!