Yeah, that is sort of a tough choice. As a solo unit I'd say that Rita is a better longterm investment due to her SAW. She isn't great DPS but she gets some niche boss utility thanks to invisibility/damage reflect, so as a third archer you pull out for rainy days she's a pretty reasonable choice. Lolonee is pretty solid for a freebie unit and makes a decent tag team with Imelia but ultimately she's a high EHP duelist that doesn't do anything appreciably different from premium bandits. That has its uses but unless you get her well cr'd I wouldn't necessarily be in a rush to develop her over Sandra or Gloria.