If I was to summon a familiar or make an animal into one, would it be able to live for as long as I would? Or would it still have the short life of that animal? And would it be unable to be killed?
The important thing is to first understand what a Familiar actually is. It is not a physical creature such as a cat or a toad as has been thought in superstition. I'd suggest reading this article so you understand better what a Familiar is and therefore how to go about creating one.
Lark has given a great resource for you on Fetches and Familiars! I would follow that!
Although it is not traditional, you can make a animal (physical) into a familiar. It has been done by many other people, and can be done by you (I've also heard amazing things that have happened, don't know if they are true or not). My suggestion if you go down this path is to ask the animal if thy would be your familiar and not force it.
According to Chaos Theory and Quantum Mechanics, if you want your animal (physical) to live as long as you would, that would require you to input your energy and intent into the animal, changing its inherent energy structure (requires a lot of energy). With the Law of Thermodynamics, energy loss is common in energy transfer, and to change reality there must be a certain threshold of energy that is reached. Although it can be done, wasting energy on changing the inherent structure of a person, place, or thing will take a lot of your time. The question is, do you want to use that time, or work with your familiar when it is deceased (If the animal or so forth wants to). As once it is dead, it can do a lot more things for you, especially if you strengthen the connection of the spirit to the physical plane (If that is what you are focused on). And the energy that would have been used to change the inherent structure of the animal would be used for strengthening the connection of the animal to the physical plane, helping your familiar by warding it with extra energy, etc.Remember, energy in magick is but the capacity to do work.
Sorry, but I must disagree. The idea that one can make an actual, physical animal into a Familiar is incorrect and based solely on superstition carried over from the Witch Trials in Europe that ended in the 1600's. While animals may be attracted to the energy of magical workings that does not make them into Familiars.
