Could it be that Raika is into Lemon, and Sunao is a loophole that would let her "date" Lemon?
This makes too much sense, I can totally see this being the way the story develops if we considered that:
1. It started with showing us her first tailing lemon
2. Her nervousness (voice cracking) when she saw lemon
3. The whole foreshadow with the president talk of outward looking pretty girls being shady AF
4. The other theory of here being the one who originally gave Lemon the idea to fake having three extra boyfriends (perhaps as a scheme to get Lemon to be single again)
5. And the most damming, here wanting to meet Sunao exactly the days that he is possessed by Lemon
Probably her plan was to start dating Sunoa and feign ignorance of their body swapping condition, while trying to only meet with Sunao the days that he is possessed by Lemon.
I wonder how all of this is going to be resolved