Really? I find that hard to believe..."biological and psychological etiology of major depression" is very broad and probably encompasses 80% of the depression researchers out there. Your questions are a bit more specific and you are unlikely to find anyone researching all of them, but it seems like it could easily fit within many peoples research programs
Some initial thoughts off the top of my head - locations might be off a bit, but I think they all worked there at some point:
Flett - York
Shankman - UIC
Alloy - Temple
Abramson - Wisc-Mad
Nolen-Hoeksema - Yale
Joormann - Miami
Gotlib - Stanford
Cuthbert - Minnesota
Half the department at Berkeley (Kring, Harvey, Levenson)
That should get you started
fyi: lynn abramson isn't accepting students. correction: incorrect information (Anne Kring looks at emotion regulation and Alison Harvey looks at sleep in relation to Bipolar Disorder and Levenson looks at schizophrenia). S. Johnson looks at Bipolar Disorder in relation to positive rumination, BIS/BAS and other psychosocial risks.
other depression researchers:
constance hammen (ucla)
daniel klein (suny stony brook)
kate harkness (queens university)
brandon gibb (suny binghampton)
edward craighead (emory university)
susan mineka & emily durbin (northwestern)
mark whisman (university of colorado boulder)
john abela (rutgers)
benjamin hankin (university of denver)
christopher beevers (university of texas)
david cole & judy garber (vanderbilt)
susan nolen-hoeksema (yale)
lauren alloy (temple)
mitch prinstein & eric youngstrom: (university of north carolina)
this should help you out. you really need to decide whether you are more interested more in a biological, cognitive or integrative approach in depression. then, apply accordingly.
you might want to consider j. pettit (university of houston), rick ingram (university of kanas) and thomas joiner (florida state)