Good starting weapon focus for a dwarven fighter in incursion? Do you start with the weapon you are focused in?
I'm confused by the dozens of options you are presented with there.
Also what decides if I can use weapons with shields? They aren't marked as twohanded or anything.
Dwarven waraxe never hurts for a dwarf, ha. They don't have to burn a feat to get proficiency with 'em, and they're pretty much "battleaxe but better". Scimitar's good, as is rapier (high crit chance in both cases, strong defensive boost from the latter). Maul is solid, though with that you'll probably want to aim for monkey grip (Power attack -> monkey grip) so you can use a shield, too. I've always been fond of light flails, as well.
Really, just about anything will
do (except maybe daggers... and even those, you can grab a level of diviner mage and pick up daggerspell for shenanigans. Blowpipes kinda' suck, at least.), so long as it's not the buggerhuge weapons (great maul, great lance, etc.), which take very, very particular builds to use (involving perked spells or items, or multiclassing, as well as particular feat choices. Unless you're a high level druid, anyway.). Probably best to stay away from the double and reach weapons (barring spiked chain, the most imba of weapons) to begin with, too. I'd mostly just say skim through
this and see if anything looks particularly appealing to you, stat wise. Otherwise just skim through the options and see if anything looks pretty to you.
As for shield, it (whether a weapon is one or two handed or not, actually) is entirely dependent on size -- player size compared to shield and weapon size. You can naturally use anything your size or smaller one handed (unless the weapon says otherwise, as per quarterstaves or spiked chains) -- this includes both weapons and shields, with anything larger than you requiring two hands. So, as a dwarf, you can use almost any medium (human sized? Forget which the game uses) or smaller weapon and medium or smaller shield together right off the bat, no other monkeying around.
The monkey grip feat will let you one-hand weapons one size up, so you'd be able to use large or smaller weapons one handed (though I
think it doesn't apply to shields, so you'd still be stuck with medium or smaller shields, as a dwarf), and shield and spear lets you treat reach weapons specifically as one size smaller, so long as you're wearing a shield (though again, I'd probably recommend not messing with non-spiked-chain reach weapons for now. They're a bit more finicky than non-reach weapons.).
Frumple, I suppose I could help out but I am nowhere close to a beginner and I don't know what a beginner really needs
Yeah, that's the problem. Even beyond that, when I was first getting into incursion just about everything felt very intuitive to me -- Inc was one of the first roguelikes I ever actually beat, and one of only three (out of hundreds played), along with crawl and ToME4, I've won more than once. I can answer a lot of questions, but figuring out the questions before they're asked is... more troublesome, heh.