Skype used to have an export to file feature for contacts in advanced somewhere. You can look around for that. If you can get it to a file you can probably import the contacts in your local Outlook/Exchange Online contacts through Outlook. Then they will be available in your Call tab. But right now, the only thing it uses or carries into the Calls tab is contacts with valid phone numbers, so for chatting this won't work.
Also these contacts cannot be used anyway for chatting from Teams to Skype since it is not supported and will not work(yet).