Re the tires, in the photo of my bike in Honduras, those are 2in tires, and while the et's run fairly well on pavement, I'd only use them for predominantly dirt riding, and loose and rocky stuff.
You might want to hold off on fenders until you're sure.
Lots of interesting tires out there. I just like the supremes but many other great options, and the 2in Supremes roll nicely and still great over rough surfaces.
My sks fenders probably wouldn't fit with the 2.5 et's but they might. I think they are the 55 model, but not sure.
Brakes-Yup for me they are great. Strong, simple, and I've figured out the technical screwing around to make them work now. Loaded the bike stops very well, but remember, I'm a light guy.
Cranks, mine are 175 and to be honest, although I thought I'd prefer 170 or 172.5, they and my knees get along and I've spent months on the bike with no issues, so for me at 5 10 ish, works for me.
Seat... Hey, personal. I did have a c17 that works well, although I prefer my leather b17s more, but again, personal...
I too really like how its nimble.