how else to pass a variable in mc2 from mc1?

mc1.somevar = mc2.someothervar;

if the variable doesn't have a var prefix, ie: if its scope isn't restrained to the function's scope, there shouldn't be a problem. You could also in the 1st MCL's onLoadInit give the mc2 variable a value, or even set it there.

That said, there cannot be an onLoadInit without a MCL, specially if you are not loading anything a second time around. So i suggest you follow the above solution.

gparis