np, it's always nice when ppl make a clear list of questions like you did. it makes giving the right advice straightforward.

you're right btw, those long can feigao's are 12x30mm. the one ppl use for DD is the 4100kV version. there are 2 other winds available i believe, and the middle one is the 5300kV that is used for gear drive tails.

about the prop: a 4540 is way too much prop. most ppl running the 4100kV motor in DD go with a 3030 prop. i ran a 4030 with my 5300kV in DD and it was smoking hot (ended up using a 3020 to keep it cool). a 4100kV will stay cooler, but i think even a 4030 might still be too much prop.

fyi, r/c propeller numerology goes like this:
4540 prop -> ABCD -> A=4,B=5,C=4,D=0
A.B = diameter (in inches) = 4.5"
C.D = pitch (inches of forward travel from one full rotation at zero angle of attack) = 4.0"

good luck, and enjoy flying with your new tail!