Which materials are the weakest? old fabric. as the material age, they become much easier to tear and rip apart. new fabric, regardless of kind tend to be much stronger.
Which are the strongest? uh. leather is the toughest, and most difficult to manage.
Which materials are the most/least expensive or desirable? I find the muslin is the cheapest fabric to acquire from a fabric store. Its a little thin, but if you sew clothes with it, I would wear a tank under, unless you have multiple layers of a sark color. Muslin is very easy to get in just about any color, and it slightly stiff so it is easy to sew with. You can get in in just about any color you want which makes it easy for color matching for cosplays. Muslin had very little strech so it can be a bit difficult if you done sew your clothes to the right size. I personally like knit fabric better. Its softer and has a better flow in the air, which makes it look really cool if you make a light trailed coat with it. It's colors are also solid, so I don't need to worry about how sheer the fabric is. It has excellent strech so if your project is a little small it can be forgiving. It also doesn't frey, but I advise hemming the edges anyways so that they don't roll up on you, and have a cleaner edge. With that said if you are looking to make a taller, still collar for example, you will need to use some kind of backing to keep it upright. but i find if you double up the fabric it can stand up for about 2.5 ins with out too much issue. Knit is a bit more expensive, and can be a little harder to get the color you want, but I personally think the investment is worth it. Satin is another great fabric, but be warned, you must hem it or it will frey like the unraveling treads of reality. to prevent this, you can hem, or cut it with a hot tool that will melt the edges. .I forget what the tool is called but it does help. (I would still hem regardless though) Satin is very slippery to work with, so pins are a must, and use more then you think you should. The other fabrics I will sometimes skip or skimp on the pins, but do not do that with satin unless you want a headache. Satin feels really good on the skin, buts its not a real breathable fabric, so keep that in mind. Its a little more advanced to work on, and remember that it has no stretch so can can be unforgiving if you sew your fabric wrong. (i have learned the hard way
) but it does make a really nice liner or accent to a piece.
Which animals can be sheared for wool, and how often? sheep and alpaca, and how often I don't know. There are also plant alternatives as well if you want.
How long does it take to weave a piece of cloth? depends on how big you are making it and how big your thread material is.
How do you make and maintain leather? tanning leather is quiet a process in which you will need to soak it in tannin or urine for a while. (you can make tannin with other material I think but you will have to look it up) then you need to stretch it out and scrape off any fat you missed before you added it to the tanning solution. then you let it dry and salt it I believe. After it is dry what do you want to use it for? if you want it for clothing, I highly suggest breaking it in, and bending if to help soften the material. Also should be noted wither of not you want to keep the fur of the pelt on the skin or not. But when working with leather, know that is it very thick, and a normal sewing machine might not be able to work with it. if that is the case you can acquire a leather sewing machine (or and industrial one) with is much stronger and will work better. you can also soak leather in water to make it more malleable if you intend on making it into shapes for makes, shoes, or armor. (of what ever other use you can think of)
Which animal skins give the best material, and why? as far an animal skins go, rabbit is nice and soft, and deer will give you lots of surface area. though deer fur is not very soft. beaver hide has thick fur, so best to keep it on. I don't have experience with much else. My dad was really into trying to make his own leather so, I have a little knowledge about this, but I am no expert. Though it it possible to buy deer hind already tanned, which is actually pretty soft and easy enough to work with. I think i was able to sew 3 layers of if on my normal machine. (though my singer machine is an old tank, and newer machine might be more finicky. )