Sweet 
First, on the subject of Tileset; I use a nifty little mod called Deeper Dwarven Domestication. It is only available with Phoebus & Ironhand, and the former will not be updating in the foreseeable future, so if Ironhand is an option for you, that's my new preferred graphics.
Suggestions: I'll start with metals. I am going off the Wiki Material Values here. Either you have cranked up the value of every metal ingame, or the wiki is horribly outdated.
Cupronickel- I get what you are trying to do, but Copper & Nickel are the most abundant metals in the game. Having their alloy be near-steel is rather overpowered. I recommend giving the alloy a cutting value ~Iron, but make it only marginally better than Copper for armor.
Solder alloy- I can't recall every finding Stibnite, but perhaps that is b/c I never noticed it due to not having any use in vanilla. Comparing the raws to other metals, this looks like it's supposed to be a half-way between iron and steel for all uses. Clarification would be nice.
Mithril- There are a lot of good blunt & armor metals, plus new sources of Iron and Iron-substitutes. I'm not seeing anything good for cutting weapons besides Cupronickel though. I think Mithril would make a good addition. It's high fantasy, but feels like it would fit in DF.
Lastly I strongly recommend checking out Stal's Armory. I ran a test Fortress and some Arena battles, and I really love the way combat plays out. I know that Orichalcum adds a few new weapons and armor options, but I really feel like Stal nailed it. If you would consider using this instead (and can get permission to integrate of course), I think it would bolster the 'enhanced vanilla' feel. Watching a few Arena battles with this might help balance the new metals & alloys as well.
All I've got for now
Ironhand: I'm... honestly not a huge fan? It was the first tileset I used, but then I found Obsidian and didn't stop using that until the lull in updates for DF2014. Also I'm not aware of an Ironhand update being available for 40.xx, let alone 42.xx?
Materials in RAWs use a different, multiplied value over their material properties. I'm guessing this is due to something in the core programming of the game, likely to do with force and penetration calculations somewhere.
Cupronickel is using real world values for between a 75ni-25%cu alloy and 70%ni-30%cu alloy, which is the approximate weapon-grade "white copper" alloy range found in ancient china circa 400B.C. - 200 B.C. Greek decorative "Orichalcum" was usually between a 50-50 to 60-40 blend and softer, about identical to weapons-grade bronze in most respects (which, granted, is a good bit stronger than German nickel silver, with only 20%ni), however again we see what was used on weapons reach around that significantly stronger 75/25 mix. Current modern use is 70/29% ni/cu alloy, with a few other metals mixed in for strength, and used in high corrosion resistant piping, some boat hulls, and a few other things for a maximum strength alloy. And the USA's nickel coin is made from a flat 75%ni/25%cu alloy at present.
Solder alloy is nowhere near even iron values, being a factor of ten weaker in.. pretty much everything? I don't think you're quite reading the values right. It's a slightly harder lead alloy that maintains most of it's weight, with an even lower melting point. Mostly just useful for bolts? But a realistically available alloy for the tech level.
Mithril: in general I'm trying to keep this mostly realistic? I included the two divine metals due to divine metals pre-existing in the core game, and my want to give players a way to access it in fortress mode. Main issue with mithril is.. I'm not entirely sure how I would exactly make it fit in, or what niche it would fill? Moly steel, the divine metals, and cotton candy already fill pretty much all the normal things that would be "mithril" in a fantasy setting.
Stal's armory: Something I would consider, but probably not be a thing in 3.0. I'll need more input, time to think about things, and then should I decide it to be a good idea, to then contact and get permission.
That said, any opinions on the whole races thing, since that's the main thing weighing on my mind for addition?
