To clarify: maybe Celtic would have a chance bottom end Championship/top of League 1. The rest of the Scottish Premiership you are probably right Conference North/South level.
The league that makes Scott Sinclair look like Messi. They could have won all their league games and I still would be unimpressed.
A bottom championship/top League 1 standard of football at best.
I bet Elvis Manu could hit double figures in that Celtic team.