The srd you are linking against is the dnd 3 srd, which you can browse here
WOTC has at least so far not released a B/X srd, this means the actual numbers your using would not be covered by the srd you are using.
I'm very much not a lawyer, but in general you can't copyright game mechanics.
This is somewhat a fuzzy line, but I'd feel safe using the generic names and stats you have.
If you wanted to use "Strahd von Zarovich" or other WOTC property thats one thing, but I don't think the names any of the monsters you have are WOTC property.
Is your notes section on page 23 directly copied? If you wrote it yourself you wouldn't need to worry about that field
If you want to point to something, I'd use either the dnd 5 srd (CC-BY-4.0)
https://www.dndbeyond.com/srd
or something like the basic fantasy rpg srd (CC-BY-4.0)
https://www.basicfantasy.org/srd/
an example monster:
https://www.basicfantasy.org/srd/monstersAll.html#stirge
the bfrg srd is based on b/x and has similar stats as to what your already using
I don't think you strictly need to cite either of these, your page 23 should be fine without copyright assignment, but I'm no lawyer