Do combinations make any difference? My first Soldier Shepherd was Earthborn Sole-Survivor... (and no, it wasn't the default char, just a coincidence). My current Adept Shepherd is Colonist Ruthless ... but it has made hardly any difference to the game so far. Even playing through the game as Renegade instead of Paragon has made hardly any difference so far (though it might be the lack of points in Intimidate that does it).
I've also noticed that according to recognition: War Hero---gets a lot of notice and reference to the Blitz! Ruthless---also get's noticed albeit people would always talk about your 'victory' not how you attained it on Torfan! Sole Survivor---get recognized by certain individuals as the sole survivor yet we all know that SPOILERS FOLLOW---
You aren't the Sole Survivor as Corporal Toombs had also gotten away from the thresher maw's clutches and survived the Akuze horror.
--- "When I'm walking a dark road, I am a man who walks alone" - Iron Maiden