Heya Mike,
I agree with Ian. Axolotls dont bear the affects of what we would call lonely.
They dont mind being in pairs or groups. So you couldnt exactly say weither or not they do better alone or accompanied.But with the right sized tank it can look stunning to see axolotls living in a community. I myself am thinking of the idea of getting a compainion for my axie Banda.
Its hard to tell weither axies beniefit from being alon or in pairs but it really depends on your prefrence. Just be sure to quarintine as Ian said, and also be aware that in case of your axie being stressed or injured, being in groups can make it harder for an axolotl to heal from these,and would need to be put alone to heal.
Happy Axie keeping!