As you say, a tricky one this week. I've always managed to complete these (eventually) but not this one. I haven't got all of the letters but I'm sure that the phrase required is
La donna e mobile - which as you surmised will be girls names in the answers to be jumbled.
At the moment I only have Sian in 6ac = resiant =reinast ;
Tamara in 16ac = catamarans = caatarmans;
Petula in 20dn = petulant = ??t?pant;
Rose in 28dn = groset = g?rs?t.
I'll persist a little longer but I don't think that I'll be able to finish it. Good luck !