As for biological warfare, I've just ordered several barrels of several venoms from the liaison. I'm going for an xbow-based fort, so i'll have to work out how to cover bolts efficiently.
I've had terrible experience with crossbow squads climbing my rather high wall fortifications then dropping down into the moat outside of the fort during sieges - be wary. Apart from that, I do not know if the caravan-imported venoms actually do something, but if they do, you can produce those yourself as well (depending on your embark, but GCS and some others should always be obtainable).
I genned a world with 1000 werecreature types, and went through about 200 of them in the raws.
Observations:
The only material weaknesses found were copper, bronze, bismuth bronze, silver, iron and steel Those were varied even over same creature types, so there was a wererhinoceros type with copper weakness, and another one with steel weakness. similarly, eyecolor variation.
There is a variety of large-ish creature types that always had the same size in the analyzed data, like weremammoths with size 9 000 000, werebears with size 500 000 and so on. Curiously, weregoats at size 200 000 are twice as big as werewolves at size 100 000.
Apart from those, there is a large variety of smaller creatures and vermin (cats, mice, lizards, opossums, rats, badgers, and so on) that did not have consistently the same size for each creature, but all the sizes were ranging between 80 000 and 90 000. This leads to things like a species of weremice being (slightly) taller than werecats. There were multiple instances of the same base creature (like werelizards) with varying size, eyecolor and material weakness.
Another noteworthy thing was that were gila monsters have the gila monster poison syndrome as well as the normal weremonster syndrome, this was the only species I observed with an extra syndrome. However, there might be some other inherited attributes that could be useful, things like shells for weretortoises for defensive advantage. I do not know if there are actual advantages to having a shell.
Conclusions:
from the roughly 200 distinct creature types observed, I am fairly confident to conclude that other material weaknesses or sizes below 80 000 do not exist in vanilla DF. Large creatures seem to have a size hard-coded, everything else gets a randomized value between 80k and 90k.
Regarding material weakness, I assume bismuth bronze or steel are the most desirable.
This means that armored weredwarves are not going to happen in vanilla, assuming the armor size checks work based on the average size (which it seems to do, otherwise
according to this we'd have about 2% giant dwarves that vastly outgrow the average human with a size of 93000 cm³, which would certainly not allow them to wear regular dwarven armor).
However, that does not mean our goals are unreachable - depending on armor size tolerance, we have to find creatures that are close to or exactly the size of their associated werecurse, which is certainly doable considering the enormous amount of animalmen we have acess to. werewolf-panda men do seem kind of silly, but who says a deadly military can't also be a strange furry fetish?
This latest proposal will require extensive testing in adventure mode, as soon as I get access to a stable DF machine I will create a world with a single werecreature type, paste in one of the vanilla-genned ones with a fitting size, play an according animalman and go kick some statues.
Giant animal people.
Elephant men, elephant seal men, rhinoceros men, etc.
I can't seem to find elephant people or rhinoceros people in the wiki, do you have size stats for them? I noticed some other animal people are not yet in the wiki as well.