I wouldn't worry about the crown or the dropouts. An internal crown is not newbie friendly. I find using brass (lfb) for things like lugs and socketed crowns to be somewhat unsatisfying. Just not used to it, I suppose. It takes a lot of heat to flow LFB into a sleeved joint of any kind.

I like tabbed dropouts, but it is a tiny bit easier to mess them up. For example, it's a lot easier to clock the seat stays properly with socketed dropouts.

You can get an ounce of silver and a pound of silver flux for less than $40. I think it's a good idea. 45% silver probably makes the most sense if you aren't doing lugs.