Caporegime
I think I read they changed that and now you need the launcher to run GTA V as well. Not 100% though since I don't own that game.
Yep you do, having it on Steam is just a management thing the game still runs the Rockstar launcher.
Got the special edition for £42.99 from CDKeys, which included 50 Gold Bars for Red Dead Online etc.
That's a very nice price, you can't get it for that anymore. At least with RS you get an extra game I suppose, plus they do state RS exclusive goodies but I'm not sure exactly what they are.