Of course, I'll bring this up but this is how stuff should generally work out.
Non-combat type xp should be determined by DC and by how significant it is. A DC15 check is about CR1/2, DC10 should be CR 1/4 and DC20 should be about CR1, 25 CR2 etc.
This isn't determined by the player's roll, so if JC wants to know info about kobolds and rolls 25, the party doesn't get the xp related to a CR2 check. Instead, relevance should be looked at, too. Since the info gained overall is pretty helpful, it might be a CR1 check equivalent, or maybe CR 1/2 since there is not much risk. Note that CR1 has very little risk overall and is pretty easy, but CR 1/2 seems more appropriate in this case.
Interactions that play very little meaningful role should be CR 1/4 at most, though things that accomplish immediate character goals and aren't guaranteed to succeed should still give xp. As an example, talking to Kaeli about her family is a pretty much guaranteed interaction, but Alain might still get a little xp (or the party might) just because learning more about Kaeli is a goal of Alain's.
Inter-party conflict, such as Fang running off and Kaeli tailing him, should be worth something as long as it's not exploited. Consider character development or discovery when talking about rewards. In this case, Fang's impulsiveness and putting himself at risk stupidly should be worth XP for Kaeli to hunt him. For Fang, this action is debatably OOC and should not be worth experience points. Likewise, JC and Alain making checks to find Fang should be worth small XP as well. Again, CR 1/4, 1/3 type xp at most; this isn't an XP farm.
At higher levels where the party doesn't get xp from CR 1/4 type encounters, these types of RP encounters should still be worth small xp. Note that CR 1/4 is worth 75xp for a single member at level 6, so that's a good thought.
Fang running off deliberately into some kind of forest with the intent of helping Kaeli learn to trail him should not generate xp unless it encourages character development.
Even attempting a failed check should give some small amount, if it leads to character development. To be honest, I feel like it should give the same (since failure is important for learning more than success is).
RPXP should probably be mostly divided amongst the party, especially at low levels. In the first game, JC would have scored much, much higher due to his many checks and accomplished goals, at 75-150xp per check. At higher levels, it can be more individual.
XP should be granted per action, not per check. If both JC, Alain, and Fang roll Survival to feed the party and successfully do so, they passed a DC16-20 Survival check together and get party XP as a whole, even though there were three different rolls. Again, CR 1/2 (about 150xp total divided between members) is appropriate, since failure costs the party money. Since the party only needs DC16 to feed itself (DC20 because we currently have 2 extra people) it shouldn't be much more since the consequences of failure are not very high.
Again, back to JC and Alain asking around for Fang; it's one check needed, so two rolls don't give more xp. Likewise for JC's double knowledge rolls; it's one task.