I think that's smart. Most of the cards I listed have left my Cube and even fell out of my on-deck binder, so I didn't think they'd be hits, but they're interesting as a thought experiment, if nothing else. I think
Benthic Biomancer and
Ingenious Prodigy are reasonably fine, but blue tends to be hard to make space for, even if there's little competition at the 1MV / XMV creature slot. You just don't actually need to fill those gaps in the mana curve with dudes in blue, really.
Nested Shambler is A+ card design, I think I might follow your lead there.
I would actually recommend sleeving up
Piper Wright, Publick Reporter. Getting even a single hit feels
really good. The power level is lower than your other blue 2s, sure, but like I said, she's exceeded my expectations enough that if she can be part of a synergistic build, she can hold her own. Looking at Drake Hatcher in comparison, the Hatcher has the same "threat of activation" thing implicit in its rules text so long as you have mana up and cards in your hand, but I think I'd rather generate tokens every time I make contact than a Drake every other time or so. That said, Drake Hatcher is *generically* stronger if you don't have as much +1/+1 or artifact or clue-specific things happening.
The Aetherspark is a must-kill threat and even holds its own in Vintage-level lists. It's like a super-equipment, really, and makes my boy
Grafted Wargear look like a peasant's pitchfork. I don't like how hard to grok it is, but it's novel, unique, and very strong. I don't like it for complexity reasons, and because I don't like giving colorless one of the better midrange 4-drops, but if you ignore those, it's very fun to play with.