I wondering what do people generally do in relation to the amount/type of information to give out to players when they use various skills like lore, inquiry etc based on purely on rolls, and how much should things be a result of roleplaying either completely with npc interactions, or just needing to be descripitve about their attempt, etc?

Your call. If the players have the skill and it isn't too low, then a good bit of rp is certainly better than calling for a die roll. Just make certain your standards are set to reflect just how difficult X clue is meant to be ... a little rp might fly for the basic clues you really want them to find anyway, but if you're looking at something more obscure, which isn't integral to the game, then make them work for it.

If you're not convinced they've done a decent enough job, then have them roll, taking their rp into account when determining modifiers.

Remember that players are not always as quick on the uptake as we think they should be, so skill rolls are a good way for them to level the playing field between your expectations and their actual ability to live up to them.

Lastly, recall that some players work hard to get good scores in their skills and may be upset if you never call for die rolls - if you have such a person in your group make certain he gets to show off his character's skill by warming some bones (tossing some dice) when the time comes ... again, with proper modifiers for the additional rp effort or lack thereof.

For many of the Lore Skills, these Skills might also be useful in augmenting other Skills. If you can't work in the Lore knowledges themselves, you can always as a back-up try to work in the Skill that they can augment (and the extra time to do the augmenting), in this way the Lore is not useless to them even if the knowledge base it represents is not being directly accessed.

Overall, though, you should make knowledge-type skills useful in their own right at least periodically, though you're under no obligation to make them useful every session.