Microsoft
1. We do not use Teams. I did at some point use it briefly and had to setup my domain that was not linked to AD. Other clients don't use Teams at all. Some of them are using Outlook 2013.
2. Haven't seen this myself nor have my clients. I can't say this is true across the board, but nearly all of my clients have the ExcludeO365ServiceEndpoint registry entry set because they don't use Office 365 and it was causing those prompts or an inability to setup an account because O365 kept stepping on the autodiscover process when setting up an account to a third-party Exchange host (Intermedia).
I can't speak for others, of course, but I should point out that some of the folks here have reported that they were working on on-prem Exchange setups. I do not. Nearly all of my clients are on Intermedia. I have one that's a heavy user of Azure/O365.
Hopes this helps.
