Yes, that was a VERY vague question, unfortunately.
There's another game I'm interested in running, but it's not released yet, though the ETA has been announced. It's a Kickstarter JRPG (and that's the only thing you'll get OUT OF ME MUHAHAHAHAHA). What do 100% runs for JRPGs usually entail? Regarding extra recruitable characters and/or hidden collectables and/or other pertaining goodies?
Each game is case-to-case. Most JRPGs don't even have a '100%' category due to ambiguous it can be, and those that do have '100%' are ran by few to no runners. Generally they'll have something that's a rough equivalent, like All _ Items.
Since your game isn't even released yet and has no runners, you'll be able to make your own categories with their own definitions. You should discuss it with others once you know what all the permanent events are.
Common examples: FF6: all extra characters; all espers Chrono Trigger: all sidequests FF5: all bosses FF4: all bosses
These generally tend to be optional story type objectives, that aren't an extreme hassle to do, and end up simply adding extra gameplay. 100% categories that include grinding to max level, getting rare drops, or other tedious things don't catch on too well usually.
As stated previously it is mostly on a game to game basis ( case to case ). Most RPG's in general have more then just the main part of the game to complete and that is where the 100% usually comes into play when going on to complete the other things or collecting things in the game before ending the game.
A 100% run of any game is most common allot longer especially for RPG's due to the immense amount of time that can be required to complete them and not to mention the amount of time it would require before hand to either route the 100% and or practice it.
Also there can be multiple variations to 100% runs as well which can conform to the above as well.
That is a very good question, since I'm actually trying to map out a 100% route for Xenoblade, lol. Kinda need to know what 100% for that game would count as. xDD