(1) I've come to believe a feature update (new Windows version) creates a new Recovery partition only if the existing one is too small. Then, it empties the existing one of its WinRE.wim, but otherwise lets the partition alone & creates a new one. But, if the existing one was large enough, the feature update would reuse it & put the new WinRE.wim into it. I've looked & seen the new size & date.
(2) Well, you can finesse it & do things your expert way with 3rd-party image makers. More power to you. But I always include the Recovery partition in my images. It's good to keep the version of the Recovery partition (its WinRE.wim) at least the same as the Windows partition. So, that time I had to restore an image, it restored all the partitions back to exactly where they came from. No fuss, squeezing or bother for me.
(3) Without a Recovery partition, not only will Shift+Restart not work, but also that trick of crashing the boot 3 times in a row won't work. Still, that won't trouble you or me, but others will have to scramble to make an Installation USB drive.
(4) I don't like the idea of setting the BIOS to Legacy in a system that has a UEFI install. I do believe, to do a UEFI install, the media must be booted in UEFI mode. I would prefer to boot it UEFI even when not for the purpose of a clean install, but don't really know its necessary.