Long Beach - Closing in 4th Bedroom

[Taylor Stone]

I'm looking for a contractor for my primary residence in Long Beach I'm looking to close in a pony wall to make a 4th bedroom. I may move out in the next year or so and turn it into a rental. This is currently a loft on the 2nd floor and there is a pony wall there so it is basically extending the wall up and adding in a door. One of the electrical switches would need to be moved about a foot over as well. I need advice as well on permitting, if an architect is needed, affecting property taxes, etc.  The home was built in 2018 and we could have selected the 4th bedroom option at time of build so I don't have too many concerns about structural.

I have a few bids ranging from $2,700 to $21k. I don't really want to do it for $20k but the lower end seems too low as well.