Lena finally found me more S5 icons and I should... probably upload them for Bellamy rofl. Here is a pretty good source with S5 and S6 stuff! I don't know why no one on IJ icons The 100 for the most part but people on DW do at least!
Jyn and her were friendly before so I definitely agree. Lucy was actually only on one mission and it was with Bellamy and Echo haha, so she'll definitely recognize her and I could totally see it too! Lexa will be happy she's around, ultimately. She has a great deal of respect for Echo and knows she's important to Clarke and Bellamy as well.
I checked back through some stuff just for funsies rofl. Echo got her Secret Santa from Oliver (but it was a different Oliver so he'd not remember) and she gave to Susan Pevensie (who is an NPC for now since our's left). We also usually have 3 mercenary jobs a month and those go through Gabriel Dutari who dated Raven Reyes when he was in game so that could be something for her to remember at some point if she ever wants to take up any mercenary jobs!
I'm totally okay with either and am always down for the more interesting/conflict/fun way to write out things, especially relationships! So totally up to you!