I'm running Icewind Dale with three players and a rotating DMPC or NPC. Lots of homebrew PC sidequests I've written in for this opening portion since they kinda missed some of the Town stuff.
They started at lvl 3 since they're new to the game and are coming in with characters from a oneshot they played together with a different DM.
I'm coming across more situations with one of the players who pick up on something an NPC says as shady or hinting at something being hidden and then he presses and presses til they either get more info or threaten the NPC. Some NPCs are pushovers, some seem strong and can't back it up, some are strong and refuse to give in. I treat NPCs with a varying degree