very good list
I would suggest leaving your low point drain caps off for most of the process. Water will continue to drip out for a while. When blowing out the lines, water needs to go out these drains. I leave my low point caps off to the time that I see RV antifreeze coming out of them and then put the caps on.
Also, disconnect the shower hose from the faucet and not just the shower head. Water will/may remain in the hose. If you have an outside hose, remove it and get all water out of it. (open valves on faucets after hoses have been removed, as water will drain back into top of faucet while taking hose off)
When I am done completely, I remove the plastic screen bowl from the water pump and shake out any liquid as it may also hold water and bust.
(the bowls are cheap and easy to replace when the frozen water cracks them, but if you have had it happen to you once, you never want to have to fix it again