I think that it is all the same. In both cases Erica returns to rolf and the shop you get is one and the same. So far the only difference I observed is that Erica's Flaming arrow inflicts less damage that Rolf's, but Erica's troops are harder to kill with the setup I'm usually using (Inquisitors, Paladins, Royal Thorns, Archmagi, 1 extra) due to more ranged units - rolf usually has tougher flaming arrow (like twice the damage of erica's) and utilized more close combat units.
As such, they're perfect for eachother
