The best gun for me is the Sniper ( If you can control it and know how to use it XD ) And then the dual snubnose ( I think thats what it called )
And bow, I don't really use bow, I recommand the 10k bow, that I used and then if you bought the Feb VIP Cupid Bow, I also like that bow, it's fast but only 7dmg and accurate.
I don't know about milestone or leprechauns because I don't really kill them ( since they don't really spawn in front me and let me kill them -_- ) but I killed over 70 leps but didn't go anything ( yet ) .
To start fire making, you need to buy the flinch from a shop called Fire Inc in Oasis, and then cut down the tree and use the tree's wood to make a fire, easy! You can also earn levels too! and ashes which you sell for 5 gralats.
And yes you need to mine in mines and get the silver or gold and then forge them in the crafting cave. ( Forging don't seemed to work for me tough )
Anyway, hope it helps!