I am just about finished in my second play thru of DS2 SOTFS. It has enough changes from vanilla DS2 that the first time you play it there may be a few annoying events, but by the second play thru you come to look forward to those. DS2 is also nice in that NG+ has changes in enemies and positioning.
The DLS for SOTFS are also pretty good, especially a couple of the boss fights.
As for losing health do to dying, you can use effigies but the loss will eventually stop at 75%, maybe? Also you will eventually find a ring that will set the loss at a higher threshold.
As for online, there isn’t a lot of action on the PC right now. I think I have been invaded 3-4 times in about 45 hours. Some bosses do have summons but I have not been able to get summoned. The game does supply a generous number of NPC summons for boss fights though. You do need to be human though, both for summoning, invading and putting down a summon sign.
As for the torch system, some areas of SOTFS are very dark and you will find a torch almost necessary. Take advantage and light things when you can, it may help. depending on your play style the sorcery that grants light is good as well.