Haha okay let's see how I go with answering. Sadly this might be the last set I answer for the day and I'll have to get back to any new questions tomorrow. We shall see.

1. Mainly medieval setting with a slight steampunk feel. Clockwork inventions, rudimentary firearms? Yes, but fairly rare. My current campaign has no firearms yet, but I will allow the party Engineer to give it a shot if he feels like it.

2. Popular weapons depend on the culture of the specific warrior. Men from the Northlands of Norbayne prefer broadswords, longknives and small leather shields along with thick leathers, fur and hide armour. Maybe a bit of chain too. Invarrians have a thing for axes and sabres and large wooden round shields. Danann generally go for light leathers, spears and bows. Naturally of course anyone
can use anything. This doesn't meant that they'll be any good with an unfamiliar weapon however. But that's starting to really get into crunch.

3. Firearms of this level are generally not powerful enough to penetrate plate armour anyway. Plate harness was often supplied with a 'proof mark,' which was considered proof that the armour was effective against gunshot. When you also throw in magical defences applied to the armour and you end up with societies who bring their heavily armoured knights to the field along with their experimental harquebusiers. Naturally of course, some kingdoms might be more steampunk than others. As always, the GM has a pretty open world to explore.
4. There are 14 base classes at the moment, the same ones that were detailed in the FAQ. This is unlikely to change, though more classes
may be added in the future. It's unlikely, but expansion rules and setting books might also include additional classes and the like. I do actually have a 15th class written up, but I have not made information regarding it available as it is another secret. Sorry.

5. It began as a D10 system but you are correct in that it has turned into a mainly D100 system.

That being said, only a set of D10's is required to play it, so I can still call it a D10 system, right?

As to balance, I'll keep it brief but magic tends to be more dangerous for both the target and the wielder whilst shooting is relatively risk-free for the shooter. That being said, we've pretty well subverted the "Annoying Arrows" trope. Kel'Serrar has been quite effective at killing things in our playtesting.
6. Every race can be any class. You are completely free in that. Some races are better at being some classes than others, but anyone can be anything. As far as a Feartarbh Duellist goes, well, I can see it. You'd just have to think of it as less of a rapier-wielding nobleman and more of a minotaur who stands upon his honour. And yells insults. It could be done.

7. Top hats? Ask your GM.

If it doesn't affect the sort of game he would like to run, then absolutely. Have fun with it.

8. Racial animosity... Well Invarrians are like a cross between vikings and pirates. They raid the Northlands constantly, and to make things worse, they aren't remorseful in the slightest, thinking it's all a game. So there's problems there. The Geardarr were a slave class under the old Bovus Empire, so they hold a grudge against the Feartarbh. Plus they have inferiority issues with everyone. The Danann view the Leathe as a delicacy. That being said, the Danann also have a habit of preying upon other sentients, meaning that they're quite feared. The Dunscarth are just unfortunate. Having grey skin and living under ground means that they tend to cop a lot of discrimination.
Now how much this comes up in game is down to the GM but the possibilities are there for plenty of racism.
9. Daemons are both those things and more besides. They're entities that inhabit the Otherworld. They long for flesh and senses as they cannot see, hear, touch, smell, feel, anything in their own forms and in their world. The Otherworld is a void where they engage in scheming manipulations which in the end accomplish nothing. They fight their wars for nothing, with nothing over nothing. Wondering how that is possible? Good. It's not. But it happens anyway. So when they get trapped by a Black Magic user they both hate and love it. It causes excruciating pain, but it is the only way they can
feel. But in the end, they want bodies. They want a way to experience the senses, so you can make deals with them in exchange for this. This is how Necromancers work.
Anyway, daemons are complicated 'creatures.' But they do play an integral role in the game.
Cheers,