Board Thread:The Panopticon/@comment-1296654-20200630105828/@comment-25041817-20200630113535

It's really up to preference really when it comes to marriage. River had the ceremony with the Eleventh Doctor, but then lived 24 years with the Twelfth Doctor.

As for grandchildren, there's no arguing with genetics and/or adoptions; the First Doctor was Susan's grandfather, and the Eighth Doctor was a different man that happened to have his memories.