The syntax error was due to a wrong definition [un1ref, un2ref,rhon1ref,rhon2ref,pnref,mun1ref,mun1ref] (mun1ref is repeated) instead of [un1ref,un2ref,rhon1ref,rhon2ref,pnref,mun1ref,mun2ref].
In order to define an array of vector finite elements, you can do as (for example)
fespace Vh(Th,[P2,P1]);
Vh [u,v],[u1,v1];
Vh[int] [ua,va](3);
[u,v]=[x+y,x-y];
[ua[0],va[0]]=[u,v];
[u1,v1]=[ua[0],va[0]];
Your code corrected with this approach:
ff.edp (17.4 KB)