W.W.
Being pre-approved is a "nice" thing to have. We are selling my dad's home since he died in March. We have told our real estate agent that EVERYONE who puts an offer in MUST be pre-approved. We are NOT looking at how much they are pre-approved for - but that they ARE approved. It can cut down escrow as well.
To see someone write $50K for a house. I think of a "tiny house" on wheels. Not a STATIONARY home. LOL!! Homes in our area aren't even close to $50K - more like $500K to $2M. What a difference.
Also - you can change your name and location. Just go to your profile and edit/update.
You also can ask your mortgage lender to give you a letter stating you have been pre-approved and not give the amount. Since your house is paid for? Have you considered taking a 2nd out on it and offering cash for the house? That would make things move faster as well.
I get what you are trying to do. But really - even if you were pre-approved for $600K - the mortgage company will NOT give you MORE than the house is appraised for. ANY real estate agent knows that. Your agent just needs to tell the buying agent that you are pre-approved and ready to make an offer.
Good luck!