ANSWER TO MAIN QUESTION
The question can be answered quickly: as far as I can see, there is no flavourful name today for the piece termed "gnurider-queen".
UNDERLYING QUESTION
So: should there be a flavour name, apart from "gnurider-queen" itself?
My response is a bit long, but I don't think we've had a post on naming fairy units, and there's certainly points to be made.
Need to distinguish between two domains for fairy pieces:
(1) in chess variants,
(2) in chess problems.
Despite substantial overlap, innovation has taken the two domains in different directions.
For the first domain, I normally consult https://en.wikipedia.org/wiki/List_of_fairy_chess_pieces, which importantly includes the source of creation where known.
For the second domain I use https://pdb.dieschwalbe.de/pieces.jsp, but there's several other lists around. Since pdb also contains a problem database, one can immediately find published problems using the piece. For example the query https://pdb.dieschwalbe.de/search.jsp?expression=piece%3D%27gnu%27 shows that today there are 314 problems with a gnu.
Gnurider+queen combines 4 basic riders: nightrider, camelrider, rook & bishop. The problem world recognizes very few pieces that are a combination of even 3 basic leapers or riders. One rare example is squirrel, combining the powers of dabbaba (0,2), knight (1,2) & alfil (2,2). The query https://pdb.dieschwalbe.de/search.jsp?expression=piece%3D%27squirrel%27 reveals 15 squirrel compositions.
Actress
There is no actress in PDB. Turning to Wikipedia, the piece featured in a chess variant called Overkill Ecumenical Chess by Charles Gilman https://www.chessvariants.com/rules/overkill-ecumenical-chess. I've encountered his work before: a prolific inventor of names most of which have not been used anywhere. (The name "actress" comes from a sequence of many related Gilman piece names beginning with the letter A.) He doesn't seem to have published recently.
If a piece is highly specific, like this, is there any point to giving it a private name, particularly before it has any use? If I had a fairy problem to publish, why not just call it a “gnurider-queen”. That way people know immediately what it does. If it does catch on as a piece type, then it can be named more explicitly soon enough.
And indeed this is shown by the fact that someone has recreated this piece for Stockfish without knowing of Gilman's energetic activity...
Glass Cannon
This comes from Stockfish Fairy Playground, although I can't find a complete list of their fairy units. The name seems completely inappropriate however. There is nothing fragile about this piece, it doesn't operate like a Chinese cannon, and it doesn't have the musketeer chess ability so it's a flavour fail. The "designer" probably picked a random figurine from those available, and gave the first name that came to mind.
Amazonrider
"Gnurider-queen can be reached from another direction: gluing a camelrider onto a nightrider-queen. Knight-queen has numerous pre-existing names, but perhaps the leading one is Amazon. The interpretation of Amazonrider is obvious, although we need to realize that a queenrider is just a queen. (In mathematical terms we would say that the operator "rider" is idempotent: rider-rider = rider.)
CONCLUSION
Paradoxically, premature naming acts as a barrier to adoption, because people encounter the name without being able to know its meaning, or as here with Glass Cannon simply reinvent the concept and give it a new name, leading to later confusion.
My own feeling is that basic leapers should all be given names (e.g. knight (1,2), camel (1,3), reindeer (4,7)). Existing widely-known combinations (e.g. queen, gnu, amazon) should be respected. But other more exotic units should first be named descriptively (e.g. gnurider-queen) with a view to encouraging their more widespread use.
This is similar to the approach in chemistry, where we named all the elements (e.g. silver, xenon), and some of the compounds (e.g. salt, benzene), but all compounds can be named descriptively in a more or less systematic way, based on atoms or known named compounds (e.g. carbon tetrachloride, hydrofluoric acid).
While that approach may work, it's dull. Felicitous combinations of powers should be given felicitous names. In this case though, I think the functional gnu-queen is brief and flavourful in its own right, evoking a picture of "queen of the gnus".
A gnu-queen on d5 can already access 39 squares of the board. Riding the gnu part only gives another 8, all conditional on intervening squares being empty. Amazonrider also subsumes the major part of gnurider-queen. So even if someone makes a gnurider-queen problem to prove a point, there's no point in a flavour name, as the piece is unlikely to occur more generally.
