1) yes more than likely its will be a limited PS4
2) only FREE TO PLAY games like Warframe, Warthunder, BalckLight Retribution and in the future Planetside 2 DON'T require PS + to play online, all other games that aren't free like No Mans Sky DO require PS + also i PS+ do basically pay for itself for the amount of free games and discounts that you get in a year but... well you don't seem like you want to even bother with it so...
3) if you are seriously only gonna buy it for Third Party games then STICK TO PC... i am a Console gamer because i prefer exclusives over better settings (FPS, Resolution etc) on third party games... i could name some great exclusives coming to PS4 that fit your singleplayer needs (that are also great games) like Bloodborne and Uncharted but you seem like the type of person who never even tries to see something from other perspectives, and will always deem some games (in this case PS exclusives) as bad games...
in conclusion DON'T BUY IT... buying a console solely for third party games and because the hardware is white seems to me very... pointless...
