Building a first batch mini, what to update?  

I would add a Super Pinda Probe to the list:  original-prusa-mini-to-mini+-upgrade-kit.

want to keep it simple, so any advice greatly appreciated

OK.  DON'T make ANY changes, build a standard model.

Use it for at least three months and learn how to use it well. Discover what, if anything, causes issues with your style of printing.  Only then consider making the changes YOU find necessary.

Cheerio,

RE: Build a standard model

Had a mk3 for many years, fixed it, upgraded it and pulled my hair out at times with it, which is why I wanted to bring the mini upto what is the current stock version with a few tweaks, there is lots of info on the R7 parts, original issues like the rotary switch high failure rate but wanted to check if I missed anything

but you may have a point

I know that @diem means only good with his advice -in sense, don't waste money if there's no need for that. Mini as it is (stock) does work, of course. But in this case, I would still say "it depends". It depends, if someone wish to have "it prints ok so far", or "the best possible" Mini.

I have upgraded my Mini during assembly and I'm very happy I did that. It just works flawless since first power on. We can see here too many times, the troubles many have when they switch to PETG... take hotend apart, clean it, check/replace PTFE -are usual advices. These things are very frustrating for first time 3D printer owner and can be avoided with Bondtech upgrade.

Old U-bolts are ok, as long we have enough feeling about how much to tighten them (to not damage bearings). I think new solution is just more comfortable and is cheap.
I don't know how good/bad old PINDA was.. but if SuperPINDA provides better precision (temperature independent!), then we want that, of course.