I can't see anything topping Goons/Chapel for the 6/2...
For the 4/4, Ironworks/Ironworks, depending on what other cards are on the board.
Again, depending on the low-cost engine cards, Talisman/Talisman could be a good 4/4.
If you open with 4 coppers, I'd consider Nomad as a first card... second card would depend on how well Nomad hit, since your second hand would then be worth 4 or 5, depending on the card order, plus the token, of course... so you'd have decent likelihood of opening Nomad/Goons or a guaranteed Nomad/Witch, or with the extra buy, you'd be guaranteed Nomad/Silver/Chapel or Nomad/Potion/Chapel / Nomad/Potion/Cellar... some really cool potentials with Nomad.
With enough good Alchemy options, I'd also be tempted to open Potion/Smithy for the 4/4... should almost Guarantee a University/Scrying Pool or Familiar before your second shuffle, and has some chance of hitting an early Possession.