The answer is yes. Mclaren are switching to the Mercedes PU, but they have to use their tokens to make the required changes. Seems one rule for some, another for the others.
No, that is incorrect. There is one rule to which all the teams agreed to. To put it very clear: McLaren agreed that their PU upgrade would cost them two tokens, but the Racing Point upgrade to the 2020 Mercedes suspension would cost them zero tokens.
I personally think that is quite stupid and unfair, but that is what the teams all agreed to. Changing it now would also be unfair and much too late in the season.