Very partial answer
I hide as a puzzle in Malaysian spoon,
The internet code for Malaysia is .my
, so this could mean my spoon. Interpreting "spoon" as Spoonerism, we might want to rearrange some letters: instead of "a puzzle in my", maybe a muzzle in pie? (Or "spy moon", but then the word "spoon" would be playing double roles.)
Bounding sturdy monument and sturdy wood.
I want to interpret "bounding" as being on the boundary rather than running. Probably there's some crossword-style letterplay going on here, and we're looking for first and last letters or some such.
Standing upside-down in marsupials' and antelopes' front,
This definitely looks like letterplay. The best-known marsupial must be the kangaroo, but turning "k" upside down gives nothing meaningful. The second best-known is probably the possum, and turning "p" upside down gives d. That d could be an upside-down p from the front of both "possum" (marsupial) and "pronghorn" (antelope).
I'm a gesture, or three, for good.
If we're still looking for letters, that could be V, as the V sign has three meanings listed on Wikipedia.