For setups like this i used simple transistor voltagedoublers
(when i had MCU to provide a clockpulse)
If i cant spare the MCU pin i use the same idea but with 555 as pulse generator .
(i attached both setups)
About your mosfets ,i would use all n-mosfets (and forget about irf540) .
Nowadays you have much better mosfets then irf540 .
I would look at something like irf1407 or something with simular or even lower RDSon .
Just have a look at the IRF website and look for mosfets for synchronous rectification .
This will save you a lot of heat in the mosfets and reduce the amount of heatsinks .
About your gatedriver ,you can either use a gatedriver ic like the ir21xx and keep the bootstrap capacitor charged with a chargepump .
(IRF has application notes on this topic)
https://www.electro-tech-online.com/custompdfs/2009/06/an-978.pdf
Or just build it discrete with a few transistors for levelshifting and gatedriving .
Both methods would do the job reliable and simple.
Good luck .