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If you are the main account holder and your AUs don't overuse the card and don't pay them you should be good and it doesn't report on your fico that they have them, but if you are an AU on someone else's account I think the category the account is under is different if you are not the main account holder. Either way, good luck on your Mortgage I'll virtually bring a bottle of champagne to the house warming!
They do in the category of Age of accounts and in terms of Payment history. I know you didn't ask but a bit more tips I recommend not getting new credit besides this mortgage, get your tax returns and bank statements in order for the last 2 years, and pay off your debts if any home loan lenders love to see low DTI ratio.