Nearly any rear derailler should screw into the hole on nearly any rear derailler hanger. So, unless you have a Surly Steamroller or other frame designed for fixed-gear or singlespeed (without a derailler, and so doesn't have a rear derailler hanger), your rear derailler should screw into the hanger. Do other rear deraillers screw in just fine? Try stuff to see if there's a burr in the frame (unlikely given the way that rear derailler hangers are produced, though).
Given your mention of Cantilever brakes, and road bike, I'm guessing you've got a cross check. Which has a rear derailler hanger.
Btw, Shimano indexed-compatible rear deraillers may have been designed for use with certain # of speeds (and 105 was 8-speed by 1993 or 1994, I believe), but they're all compatible. So a 105 rear derailler from 1987 that originally came with 6-speed indexing has the same cable-pull ratio as modern Shimano 105 or Ultegra or XT or whatever rear deraillers. Your shifters need to match the number of cogs, but as long as you're working with Shimano indexed-compatible rear deraillers (excluding pre-9-speed Dura Ace) you don't need to worry about compatibility.
On your front derailler, I'm guessing that you had an aluminum frame (with fatter tube) before and now the Surly takes a FD with a 28.6mm clamp. Just grab a Shimano FD on eBay, make sure it has the right clamp diamter. You can get them cheaply. With double-chainring setup the front derailler adjustment and compatibility isn't too finnicky.
On your brakes, you just need a straddle cable. Can pick it up at your LBS for not too much money.