Genji appearing is cool, I'm not expecting a ton of focus on him just maybe he provides lore on Kingdra and some Dragon-type knowledge. Genji is a character that humbled AG!Satoshi's attitude so it's quite cathartic he'd work as a form of a "guide/teacher" for Go who wants to be stronger and independent in his Project Mew missions.
He already had a bigger issue needing to be "saved" by Tsurugi/Asahi but he was already being really intiative during the whole plan, escaping the trap, saving the eggs, putting out the fire, type advantaging the wild Pokemon. Seeing Inteleon battling underwater against the other "Sniper" Water-type with improved battling skills feels like a natural progression of Go's strength in that aspect.
Using Inteleon for this battle is actually really cool as well, it seems to be using Liquidation or some super cool looking underwater rendition of Snipe Shot. I'm so glad Inteleon gets such an active role in Project Mew, it's very fitting for the Secret Agent Pokemon. Another possibility is maybe we're seeing Inteleon against the wall activating Torrent to power up Snipe Shot.
So unless they are really being misleading, Goh will have to actually catch Kingdra and not just get its scales. Whether or not he gets to keep it is another issue though.
And while not as 'legendary' as Volcarona, Kingdra is pretty impressive itself when going by its dex;
The yawn of a sleeping Kingdra is powerful enough to create undercurrents capable of destroying small ships. Should it decide to emerge from the depths of the ocean, Kingdra's strength can create large whirlpools and sea-born tornadoes on the surface. Because of its immense power, Kingdra often hibernates deep in uninhabited areas of the sea to rest and build up its energy. When a storm arrives, Kingdra is said to awaken and wander about in search of prey. Kingdra is known to have fierce battles with Dragonite whenever they meet. The scales shed by Kingdra are given to royals as gifts due to the gleam it emits.
I always appreciate it when Go gets those catches of grandeur, missed opportunity with the golden Ulgamoth but he only came for the scales and probably wanted to leave it to its home.
Since we had an episode on Dragonites lore, its nice that we get one for its rival Kingdra. Would be interesting if Kingdra is the one pokemon that Ash's Dragonite can't stand.
I really like this idea a lot! It would also offer a chance to give Kairyu more characterization than appearing as a perpetual sweetheart. We've seen its competitive and caring side plenty. It was taken back by Iris's more sirly Kairyu. Giving it a more "negative" relationship with another Pokemon like Kingdra sounds good.