@Erinç1 There are host, co-host possibilities, but the simplest thing would be for you to host under one account, since you're going to be spelling each other off every few months- have a profile with a photo of both of you and both your names. Couples do this, parents and their adult children, there's no reason why a couple of friends can't.
Then you would both have access to all the same information and be able to message guests from the same account.
Airbnb doesn't have any interest in who owns the homes they list, you don't have to notify them about any of this, and they won't pay a portion of the income on one listing to two separate accounts.
As far as the taxes are concerned, that's something you and your friend/co-owner would have to work out. I don't know how Airbnb issues the tax papers when the hosting account is joint, but other hosts here probably do.
I would suggest that you have a legal agreement with your house partner regarding your arrangement, that covers how the business will be handled.
Friendships can turn sour if you don't keep business as business, rather than just trusting the other and having verbal agreements because you are friends.