l want to see Arctic Monkeys

As this is in the Immigration section that will depend on if CBSA will let them in. They won't require work permits as they are playing at a venue that doesn't require one as per Reg 186(g) of IRPA. If they are all Canadian citizens then it won't matter if they are Canadian Arctic Monkeys.

Is the lead singer able to set himself up as the "Boss" of the band and bring his bandmates in as TFWs?

Yes but they won't need work permits so it wouldn't matter if no Canadians had auditioned for the band. If they played in a bar then they would have to apply for LMOs. I'm not sure if LMOs would be granted if they were playing in a fast food restaurant although their NOC code is not on the list of jobs affected by the current moratorium.
If they did employ band members from other countries such as Jamaica, Guatemala and the Phillipines I really think they should consider changing their name.

Yes, is the answer I think. Bastille and Ellie Goulding were sell outs last month, but in smaller venues. Buy tickets!

Cheers Ann.