I know it's my ignorance showing here, but their outfits don't look all that different from their usual wares... aside from the visor and spikey ballcap that only bothers me because I keep thinking about how to clean it without ruining those spikes. Disregarding my weird concern, the posing is interesting. I imagine the normal method would have been to merely place the visor over Marina's eyes. Her lying down and having Pearl in her current position certainly implies a few things but it's the subtly worth appreciating. Still, it really does seem like their summer-specific costumes are just headgear and a color swap of their outfits, but, again, I don't play the games to know if there's more to these costumes that I didn't notice.
Side note - your strong passion towards a casual hobby on these works help distinguish your style. As long as it doesn't disrupt your personal health and social life, I don't see a reason to be bothered it... or to "curse" yourself. Heh.