Up where I am the casing is steel . Little tougher to drill I like the idea of sleeving the pump wire I've had wires chafe and break I'm sure you did it but smearing some silicone grease on that adapter and o rig is a good idea
I like the idea to put 1" Polypropylene Conduit to protect The Wire. I wonder why you did not keep the conduit all the way to the top? Also, there is 1-1/4" CTS 250 PSI Poly Pipe available - why not to use it? It will not reduce the diameter from the pump and can withstand more pressure.
Many Municipalities require the well head to be 18" above grade to prevent surface water contamination (from rain and flooding) cutting below grade is a no no.