you get 60 days upon arrival so dont need visa. Where to stay also depends what you want to do Bangkok is big. I personally like IBIS riverside nice clean rooms, great location and good breakfast
Would advise checking here to make sure you have everything needed for your daughter. I think you should be able to get passport at Thai embassy before leaving.
Lots of cases i have read where children need go back get info from embassy where they were born. Just double check they very helpful there.
You can check here, but as someone who imported large boat before they go through it with checking individual items. They used exchange and mart (uk website) in my particular case to check value of items. (Dont undervalue)
Yes my wife never had no issues even before we were married, first time she went to UK she came for a weekend for my dads 70th. Met me in UK I was on ship and flew in from trinidad. But she has good job and properties