1. Are there hotkeys for attacking and casting spells?

2. What skill is equivalent for spears? Just got a level up and not sure what to focus on with the fighter, who has a spear.

Not coded into the game by default, no. The actions were designed to be executed with a mouse in mind. There isn't one (as to the why, this becomes evident when you realize that the spear you can acquire from the Skeleton Warriors is the ONLY spear you'll find in the game).

If your fighter character is on the front line, be ready to ditch the spear for something like a sword or (the somewhat less reliable) axe.

If attacking from the back row is a priority, putting points into the Assassination skill should be the focus (which would also eliminate the need for the spear entirely).

Thanks. I'm doing OK so far at level 3 but might have to do something about it later because whenever there's a more stressful situation I either watch the icons too much, missing the action and walking into corners or being surrounded, or I'm watching the action too much and missing the small icons. I know it's a throwback but It feels inconsistent with having keyboard shortcuts for movement and inventories.

So assassination has double reach? Good to know.

Should be unlocked when 10-12 points are put into it (I forget the exact amount).

Also, in regard to potential hotkey usage, there appears to be this thread which has an AutoHotKey script in it. I have no experience with this sort of thing so I can't offer advice on how useful it is or isn't but if you're familiar with it then it might be worth a look.