I don't really think the voltage regulator on the charge pump is necessary either but found space for it just in case it was, I only takes one link or a 15 second edit and its gone. For that matter one 5 volt regulator for both signal and power will probably be ok.
The discreet regulator is for high input voltages ie 50v I'm not aware of any common high voltage 3 term regulators, also it splits the dissipation between two devices. Again it can be bridged out if not required.
The 244 takes up slightly less space than a few transistors would and is a bit less fiddley to put together. Paralleling is necessary to get fast enough switch on and off times. I have arranged it so that more gates are used for turn off, the idea being to have turn off occuring before the upper mosfet turns on to avoid shoot through. Some of the turn on gates will probably be disconnected in the final edit to get reasonable symetrey with the high side drivers.