He's bought in to help as he's a spare part and the time patrol has got busier.
1. Which TL is he from.
Is he from the main timeline?
Unseen?
Two trunks?
Cells?
U12guys?
We know he's not the original trunks timeline as he died in the sword there.
We know he's probably not from the U12 guy ones as that's incredibly different to the main timeline, in that there's no Trunks (otherwise there'd be a second set of timelines branching off that and more time rings)
No one set him loose in Cells.
They've never touched the unseen in any other capacity so I think it's unlikely they considered this, also probable that no one released the sword there too.
I think he talks about buu events as if he was there so he's gotta be main instead of two trunks right?
2. Is he plucked out of time from the present from supers perspective or she got him in the present year of her timeline? (This ironically gives elder Kai greater plot armour then even the main cast appearing at the end of the manga haha)
3. I found it weird Shin wasn't in the game at all and wondered if they dodged a bullet not including kibitoshin but The chapter came out the year before apparently. They dodged a continuity bullet not including him in xenoverse 1 fused up! This was originally a question but I found the dates myself. I don't think we even see him in a cutscene.