The only way I could see a Charisma-Investigation would be if what you are investigating has some sort of sentience you can influence. Maybe you're investigating the door of an illithid vessel or something, so the door possesses at least some sentience in a way...
Sorry, just a combo of busy/vacation/nasty Covid case (coming out of that now) which is causing the delays on updates. I'll hopefully be back posting here soon.
Nothing went missing as such - everything just got squeezed closer together, and some directions for areas might be different depending on the empty areas that got cut (literally - they have pictures of them taking scissors to the map). As an example, Erlkazar, an area in eastern Tethyr, got...
They do. Using the Study action, you would roll Arcana for information on Aberrations, Constructs, Elementals, Fey, and Monstrosities, Nature on Beasts, Dragons, Oozes, and Plants, and Religion on Celestials, Fiends, and Undead
It shouldn't be too hard, since, although the timeline did advance, it didn't advance by a lot (compared to the disaster of the 4e timeskip), so most of the NPCs and locations are still valid. The 3e FRCS also had a history section that focused on recent years, which helped bridge the gap a bit.
It's rather interesting to see arguments over something that the Study action was explicitly designed for.
"Can I use the Study action to recall if a troll has any weaknesses?"
"Roll a History check, since trolls are Giants. And since one particular weakness is well known, roll with...
The Dalelands were always my go-to spot for 2e and 3e campaigns. I was quite annoyed that 5e sidelined the region, and was conversely quite happy that will be featured in the upcoming books.