I tried to make my picks mostly different than other MHA X Heathers picks so this is not boring to read. 

Bakugo = Heather Chandler

This is one of the two I picked that other pick. Bakugo fits her role nicely. They're both short tempered bullies than are jerks. 

Todoroki = Heather Mcnamra

Most have Denki or Kirishima for this role but I gave this slot to Todoroki. They're both suicidal and have low self esteem. Mcnamra doesn't care for Chandler like how Todoroki doesn't care for Bakugo.

Monoma = Heather Duke

They both think that they are better than others. They are both a little bit cocky and feared in their classes.

Jirou = Veronica

They are both headstrong but logical. They both are quiet but sarcastic. They both keep a level head most of the time and are brutally honest at times.

Uraraka = Martha

They wear pink and are constantly happy. They are both very supportive towards the main character and is positive.

Mineta = Kurt 

They are both very perverted and rude. Also I really just want Mineta to sing Blue.

Aoyama = Ram

They both are thought to be gay. They both love attention and are a little rude.

Mt. Lady = Ms. Fleming

Both have a ton of energy and like attention. Also I feel like Mt. Lady would sing Shine a Light for some reason.

Denki = J.D

Oh boy... This is kind of a crazy choice but hear me out. It more like TRAITOR Denki than Denki Denki. They are both have mysterious dads that we don't know a whole lot about. They both are defensive of people they care about and they both have black coats. Also I couldn't resist so many puns between J.D and Denki. You'll see in Freeze your Brain.

Thanks for reading! Sorry these picks are silly and most are certain roles for stupid reasons.