Neelix was the local who knew about the area of space they were in, so I'd say it's reasonable that they were pleased to have someone who might at least help them avoid some of the worst of the local hazards that they could (like, say, for example, pointing them away from something like the Krowtonan Guard, who took out half of the Equinox's crew - it's easy enough to picture him saying 'oh, I'd avoid this area, there's nothing of use to you here, you should go in THIS direction' without even mentioning the Guard proper).
Kes, at least to begin with, was a tagalong with Neelix, but as she became the Doctor's medical assistant, we saw that the crew appreciated her gentler approach to him plenty of the time. Plus, given her personality, I'd say she was someone the crew in general was fond of, because she just had this gentle and eager to learn air about her that I would think would put them at ease.
Now Seven is where things get trickier, because I think there SHOULD have been a lot more attention given to the crew struggling with a Borg among them. We had B'Elanna's hostility, particularly in The Gift and Day of Honor (plus an additional bit in the novelization), but it wasn't ever really given the focus it should have, I feel. Sure, we had Janeway making it clear that she saw Seven as a victim they had rescued from an abusive home, for want of a better metaphor, but Seven also represented this existential threat to them, surely it called for some additional pushback. But, that would also have depended on Voyager, as a show, developing the crew outside of the main credits cast and being able to have a lower decks perspective.
Given Voyager's unique circumstances, where not just was the ship lost in an area of space 70000 light years removed from their own frame of reference, but they were also a melding of Starfleet and Maquis crew, a mix of people who choose to explore the unknown and people who were just looking to defend their homes from the Cardassians, I think they were generally pretty accepting of people outside of the typical "chain of command" having a position of prominence in the ship's hierarchy. After all, there was a decent chunk of the crew who came from outside of the typical chain of command. Not like it was a new thing on Voyager.
