What matters is the pixel pitch. If you cram more pixels into your sensor, it will display bigger and print bigger.
The 645z and K1 have the same pitch as the K5 (because that was the optimum ratio for quality), so a 25mm object will use the same number of pixels on all 3 formats. And the actual object will display the same size (the larger formats having more around the edge to crop off).
The K3, will create a bigger image because it crams more pixels into the same area.

Fab. Love number two

You don't really save stuff in Lightroom. You process photos, non-destructively and it saves your edits in the background as you make them. All your work is recorded and you can go back to any state, at any time.
It will then process your photos for web, or print, or simply a slideshow. all without saving or comitting your edits for ever.
If you do want to save a file, you can use any number of export presets. Lightroom is all about batch processing and library organisation.
Photoshop is for individual files and deep (destructive) editing (work on a copy )

The Metz will need a receiver attached. The newer Yongnuos have a built-in receiver.
None of this will enable HSS off camera.

I've always considered the Tamron to be the best value fast wide zoom. Better than the 16-45 or 17-70 imo.
Mine is a solid performer, even wide open in poor light. It's the one I choose for astro and sometimes weddings and events if I need to be adaptable, but the photos don't exactly jump out at me. I don't think I have any that I would consider exeptional, but I think the same could be said of any of the other zooms and if I need that sort of quality, I put a prime on.

Number 1 is the stand-out image for me. It's quite sublime and would print absolutely enourmous
If I had to be picky I would like to see a smidge more bottom and less sky. My personal trick for gettting less sky but still retaining it, is grab the top rectangle, squash it down with the transform tool and crop the (now empty) top off
Fab. Always love seeing your work Bill.

Yep, that's the one.
PC too, that's good

Look up Perfect Browse 9, not sure if it's available on Windows.
I have it on my Mac and it's very fast to display images, but I don't need it as I have Lightroom (which is a bit slow to open images at full res).

This is interesting; I haven't considered this issue.
As a graphics/photography/multimedia guy, the CC route is essential for ongoing compatibility with other people, but the idea that I'm stuck in perpetuity and unable to edit my own photos is a bit scary. Luckily, I routinely save as TIFF, so I'll probably be fine and simply have to revert to using a normal file browser to organise my files. Lightroom is a batch productivity tool more than anything. For individual files, any version of PS is just fine. So I guess I'll just have to work slower one day, when I bail out of the rat-race.

Very striking. Not particularly my taste in processing, but I'm sure they would be very popular.
I think all but the last one are listing to the right. The ellipse needs to be absolutely horizontal.
Frustrating getting up and traveling somewhere to be thwarted by clouds eh? But you've made the most of it.
Can't make my mind up which one I like most, that's a good sign