Brondby are certainly a better side than St. Mirren (although I would say the Danish Superliga is a pretty similar level to the SPL), they play more attractive football and half 3/4 decent players.
Their key players:
Johann Elmander - Former Bolton and Galatasaray striker, beast of a man. Actually would have been a good partner for Villa here, he's a bit like Nemec (big strong/good in the air etc) with a bit more flair and guile.
Daniel Agger - Former Liverpool centre back, great on the ball and in the air, strong as an ox. Would still walk into most Premier League sides.
Teemu Pukki - 24 year old Finnish striker on loan from Celtic. Has 5 goals in 11 games this season. Very skillful and a good finisher, he's a talent.
Thomas Kahlenberg - Experienced attacking midfielder and captain. A bit of a talisman for them, creates a good lot of chances for their strikers.
Others to look for: Rashani, Ornskov, da Silva.
I would play this team for the 1st Half:
Saunders
Williams Hernandez Mendoza Wingert
Poku
Ballouchy Grabavoy
Mix
Nemec Villa
and this for the 2nd Half:
Rawls
Brovsky Facey Kwame Brandt
Jacobson
Dunn Calle
Velasquez
Taylor Shelton