That last one certainly isn't Helv due to the 'a'.

No, its not Helvetica.
As you can see the "M" is not the same.

Preußisches Bleisatz-Magazin

Whoops, Georg. You missed the first part of Gary's post. He wonders about the shapes beyond the M.

You could flip the "W" for the "M" to use it as such. The Munich Olympics '72 did so for the "WM" sign I think.

And it gives the logo a brandnew meaning: Wc Donalds :-D

I have tried to do subvertorial stuff with the McDo logo and it's different enough from Helvetica to make it pretty hard to do.

Custom, then? For a company that big and universal, there's almost no reason not to do it.