1. I suggest you read Harrington tournament series, Harringot on cash games for live 1/2 NL , every book you have from Sklansky and if you like to start online first, then read Harrington on online cash games(in my opinion the best book for micro stakes NL).
2. It is up to you
3.If you have bankroll then live 1/2 or online 10nl
4. LHE and NLHE are quite different games in terms of strategy but there is no harm in learning both
5. Yes, if you can afford HM2 or PT4 then you should definitely get it. You can totally be a winning player without those(especially at the micros), but your win rate will be higher if you use one