Xenomorph that attacked Wendy

I don't think it was from an animal as we saw that chest exit wound from a human in the cryo pod. However it moves similarly to the runner from A3 and that one burst out of a dog (or an ox depending on which version you watched) 

That orange cat we saw in episode 1 was merely fan service and a throwback to the OG orange cat Jonesy from the first Alien. 

There is more than one version?

Yes the official release versions are: the theatrical version and the considerably longer and better "assembly cut" released in the early 2000s I believe. 

The Xeno which attacks and is killed by Wendy was born from a Human on-board the Maginot prior to its crash. "WHO" still remains a mystery, however.