Been a while sine I posted an update. This part of the project is over and completed. Now to have the walls and ceilings closed up. I still have a rear bob to do, but it piped, valved and plugged for now. Also I left a little copper at the kitchen sink and will do that over the summer. Still debating whether to do copper under the sink or pex. All pressure side copper (hot water heater, master shower vale and feeds as well as tub/shower valve and feed) have been replaced with new L copper and new valves. I figure if junk copper lasted 37 years L should last until I am dead. Some of the reasoning for keeping and redoing copper for showers/tub was to get the same exact valve I had before. I had contemplated (even ordered) new Delta valves and diverters, but Delta and the new universal Moen stuff would have required too much rework as the diverters exit on the wrong side compared to my existing Moen 3375. I found a new 3375 on Ebay and bough new 2570 and 250 valves to keep all existing trim and exit side piping in place.
Drywall people come in 9 days and then I am back to normal. It took 3 months from when we started to open walls to done. Never went without water other than cutover day and that was 9 hours without. Lost 2 weeks due to a flu or something. and other than the cutover week all work was done on about 6 hour shifts on Saturdays. I still need to tally up costs and such once I return a bunch of pipe and fittings, but conservative estimate is I saved myself $3K likely closer to $4K and walked away with about $1200 in tools (Pex expansion, new drill, reciprocating saw, rotozip, impact driver).
I definitely underestimated the effort, and at times wondered if paying a pro to do it in 4 days would be better off, but considering I did things exactly how I wanted them and did not take any short cuts I am still leaning toward worth the effort. It is a good feeling to do it and I learned a lot about what to and not to do.
And I have a new found respect for plumbers that do this every day as this is wear on your body. And a very special thanks to folks here especially
@Twowaxhack for a great deal of excellent advice.
I posted more pic in the previous link and will update more in the next few days. I have tons of before and after shots and videos. I hope to place some videos together with narration and post to YouTube in the coming months.