You can obtain second stages of all three pokemon in friend safari though metang and pupitar require you to have six badges.
If you don’t have 6 badges or want traded pokemon for those lines, then I can trade you the first stages of all three for free though I’ll be able to trade in about 20 minutes or so. Any preference for natures?
You’re right, online name(Dechozen101) is the one for trading.
Here’s an online features guide that has a section about trading.