Perhaps. If I were in the Gulf area I would be more worried about the barometric pressure than the wind speed. If I recall correctly, the storm surge is almost entirely due to the low pressure in a hurricane (though I could be wrong). Obviously there is a relation between wind speed and barometric pressure, but since a hurricane is a very complex beast, it is a very complex relation. I'm paying attention to the pressure which indicates that a Cat 5 storm surge is heading towards Texas.
Nope, the storm surge is mostly due to the strong winds piling up water in and near the eyewall. The low pressure maybe adds 3 feet at MOST to the total surge. Also, as has been mentioned by others many times, the actual central pressure of the storm has nothing to do with the wind speeds. What matters is the pressure gradient between the surroundings of the storm and the center. The higher the "background" pressures, the stronger the winds in the eyewall will be for a given central pressure, all other things being equal.
So, DO NOT go by the central pressure alone to get wind speeds. This is why recon is so important.