Generally, I would advise loading the game to the point before you started killing any NPC you can converse with in this game, as the only NPCs that you have to kill at that point are mostly Batlin's minions who will reveal themselves as such. In the Sleeping Bull Inn, there is also a sorcerer who can sell you spells available only from him only when you are about halfway through the game. The hourglass of time is the only way to resurrect characters, but it is very specific only for your three companions plus Iolo's spouse (not recommended to use it immediately on her either as you need to do something else and speak to her at a certain location after resurrecting her).

Therefore, I would recommend loading the game before you approach the Sleeping Bull. Restarting from the beginning would be too long unless you didn't save game in different slots periodically. Did the NPCs aggro you because you were running away from combat with hostiles as you approach the Sleeping Bull or did you miss the part when Selina reveals herself to be in league with Batlin's minions outside the Royal Mint and she teleports away leaving you to kill all the minions who show up there as you were leaving the building with the gold bars?