"Governor" is part of the engine controller calibrations. Speed limit is mainly due to speed rating of OEM tires.
The factory radio display is used for several non-radio functions that you will lose if you replace it with aftermarket (Outside Air Temp Display; Driver Info Center (trip odometer, range, fuel economy); Ability to personalize some vehicle functions; Warning messages (too numerous to mention but in your owner manual).
I don't think you will have to worry about Oil Life warning if you replace the radio because the warning message pops up only on radio display. It does not turn on the low oil pressure telltale in cluster. I think you can reset oil life function another way using throttle but don't know the procedure.
If you replace radio you will still have chimes working since the instrument cluster contains noise making device. However you will occassionally hear a chime that you won't be able to explain since the radio display won't be there to tell you what the vehicle was trying to let you know.
The remote start will still work with the radio removed.