You can inspect the starting 7's personality profiles before embark, and either accept or reject back to the embark selection map screen and try again until you get results you like.
Which can be a real pain if you're as picky as I am. I wish the game offered you the choice of which to select first: The site, or the party, and then allowed you to save your progress. That'd allow you to build "the perfect team" and save them to embark them wherever, or generate different starting 7s over & over without having to find the destination all over again on every single try.
You don't really have much control over the physical attributes and preferences displayed on the personality page though, so it's a bit of a crapshoot.
Yeah, I allow myself a little bit of cheating on that one: Immediately after embark, I'll allow my dwarves to exchange stats & traits--if Dwarf 5 has an iron will and Dwarf 1 doesn't, I'll have them swap. I only have Runesmith, though, so I can't edit preferences.
Dwarf 4: Broker. 1 rank of Appraiser is all you need.
You don't need any points in Appraiser, as you get a boatload when you commence trading for the first time. The only advantage to starting with Appraiser skill is that you can see your fortress's wealth before the end of Autumn.
One point of Judge of Intent is enough to let you see the trader's mood, which will give you a very rough guide to how little profit they're willing to take. You can force-train this skill by making numerous small trades, but it'll also train other social skills. So maybe you should let Dwarf 1 be the broker for a while, and then retire him once he's cornered the social skills market.
Spending 5 embark points is
worth going to the trade depot already knowing that a -gold figurine of dwarves- costs a lot more than a +chicken leather bag+. I don't worry about haggling merchants down to the lowest they will tolerate, I just give them a 100% profit margin. They get a nice deal & bring more stuff next year, I shove some surplus crap off the edge of the map. Win-win.
I don't like the idea of socializing the mayor through trade because a) the duke doesn't like it when he keeps seeing engravings of himself weeping because he was removed from the position of broker, and b) maxing out his social skills at embark is the only insurance against the inevitable craptastic migrant with batshit loony preferences . . . who also just happens to be a Talented Consoler.