Mew two could want to celebrate the MC birthday by being the cake. Some frosting on her while she levitates the candles. Could go with the birds making food since they were the first legends he meet so them working together and the player choosing which to interact with first for the birthday party. Mew could be a present with a bow around her and could even have mew two a little embarrassed like when a daughter sees her mother in an embarrassing way in front of others. It would be funny and a good event for the very first legendary Pokémon of the Pokémon series. This could happen just after when the first set of eggs hatch and the MC mentions that the children will share the same birthday and explains it. the legends ask if he has one and can say yes and coming soon but has not celebrated one in a long time. The first legends would decide to make one for him to show appreciation and such.
If the pull ups are too tricky to write could also do "push ups" with the MC on ground but them still giving BJ till they inflate.
For the plant type legends their weakness could be their feet since to a plant having their roots damaged or messed with is very effective at damaging the plant since leaves and stem can be damaged without to much impact. So to plant Pokémon their legs can be considered their roots and be very sensitive if targeted. Thus they could give very good foot/thy jobs to the MC while getting massive pleasure from it.
For ghost type they could be the type that get heightened pleasure from doing the act in public spaces. Ex: MC at a desk/table surrounded by people and feels her her give a BJ just below the table and must keep a straight face or be found out which gives her a thrill at the danger of being found out. The ghost can go invisible but wants to do sexual acts in places where many people can gather and could find out about her but since they are so good at sneaking they keep pushing the limit to there skills that they are so proud of. This does not have any bondage involved like the darkness but still an almost embarrassing situation involved.