I think it was a full power Big Bang Kamehameha either way. Gogeta seemed genuinely surprised when Yi Xing Long survived that attack, he expected it to be his end.
Probably within the year. I hope someone other than Toyotaro does the story though. Like how Boruto's story used to be done by someone besides Masashi Kishimoto or Ikemoto.
Depends how old Jiren is. With how Belmod was suggested to have left the Pride Troopers to become a GoD, Jiren might actually be almost as old as the Hakaishin in which case he may only be slightly weaker than in the ToP.
I think they existed, but primarily in Generation 1 when the worldbuilding was still in its infant stages such as the country USA being named in Pokedex entries along with Raichu being stated to have enough electricity to zap an elephant into paralysis or whatever. These traces seem to slowly...
I'm hoping they have better movepools than in Tenkaichi 3 if the characters keep getting divided into Goku (early), (mid), (end) and whatnot. BT3 had some bad movepools at times like Goku (mid) using the Meteor Combination he used on Piccolo Jr. all the way back in the 23rd arc, or his (end)...
Gohan had sharpened eyes in the DBS anime even prior to reunlocking Ultimate so I don't think that's much of an indicator here. He's not a warrior anymore in GT, that much is evident going by official sources.