In the end, you gave Ai your book without a second thought.
You wondered for a couple seconds if you could fuse the lobster plant to her Nimble Mantis Shrimp; but like Wang Zi dolphin the element mismatch is too wide for the fusion to work.
Same for the thought of eating the lobster with Yuzu : it's made of burning leaves for one, and second, you'd have to break the spiritual bead and maybe kill it. Clearly not worth.

You elected to pluck the Yuzu, letting Moss work on the graft.
You decide to experiment with the first one : surely, using its juice in the teapot could maximize its yield?
>Never worked with Immortal Cooking
This had chances to work. However, you just wasted one Yuzu as you heated the juice. You try not to take it bad, and cope by telling yourself this was a matter of luck as you're pretty sure there was a way to use smartly the Yuzu with your teapot. Way you don't see - however, you feel you could really take an interrest into how Immortal Cooking works.
To avoid any kind of issue, you simply eat the second fruit. Surely, its energy will help you on your cultivation.

Then, there's the whole "Whale-Pen-Building thing.
>Learned formation : Beasttamer Pen Formation!
>Takes 2 days to build, 2 days of Ritual. Need a physical pen of materials at least as strong as the spirit to hold, and element of spirit stronger than the one to bind.
Weaving together branches and foliage near the basis of the tree to create a head-sized ball on the outside, large enough for whale inside. The tricky part is filling it with saltWater, according to the instructions that were given (you're not trusting anyone except Moss to that precious tree of yours).
"This steward remains Young Lord that according to his tale, the acquired Whale -
- ... doesn't need Water.
- ... You understand fast, once you've been longly explained things. And isn't your World-Tree Wandering?"
In case the Whale Bead breaks, you now have a failsafe. And a Pen remains a boon for a BeastTamer.