"They wear white sweaters."
'それら', ’あれら’ is natural.
'それ' and 'あれ' do not have life. Almost 'たち' is polite than 'ら'.
Both '僕たち' and ’僕ら'.
I have searched. '猫たち' is many than '猫ら'. It seems. (Social status of Cats is high in Japan. lol ) ＊I didn't have opportunity to use both 猫たち and 猫ら. I said only '猫'. Because I do not have cats.＊
By the way I had surprised that the plural of 'he', 'she' and it are 'them'. 'He' and 'she' are creatures. 'it' is the object. Why the same word is used?
＊update＊ I haven't had the opportunity to use either '猫たち' or '猫ら', because I do not have cats.
Replying to your question about he/she/it, which all become "they", it is because he, she and it refer to what we call "the third person". That means talking about anything that is not one of the speakers of the conversation (so anything that is not "I"/"me" or "you"). And in English, all of those things or people who are not participating in the conversation are called as "they"/"them" when talking in plural. Actually, I don't think that English grammar makes any difference between living or non-living in any case.
I hope that was a little helpful. If you wanted to know why the word "they" was created to mean anything in plural outside of the speakers, I don't know about it
*I haven't had the opportunity to use either 猫たち or 猫ら, because I do not have cats.
(The "have done" form - AKA past perfect form - is used when talking about the time period starting in the past and continuing until the present moment. The "did" form - AKA simple fast form - is used when talking about something that happened at a specific moment in the past.)