You can use any lens/camera in light rain, and they might survive OK.
Weather sealed kit should be fine (but is not guaranteed).
A non weather sealed lens will probably get a little water inside - there will usually be no immediately apparent problem with this - but there's an increased chance of fungus growth subsequently.

The lens description includes AF, a feature not present on the ME super. If it has AF it will be compatible with the K-1 (The ancient ME-F being the only exception, and not one you're likely to come across).

K mount is just about the most backwards compatible mount there is. AFAIK all K mount lenses should work on the K-1 though there may be restrictions:
Most importantly some of the third party variants with a RK mount have an extra electronic pin that can catch in the AF screw drive of Cameras. Don't use RK lenses without checking! If this extra pin is prominent it can be removed.
Some (the DA range) designed for earlier digital cameras will usually not give full coverage, requiring cropped mode to be used (or showing severe vignetting).
Many earlier lenses will be manual focus only. They work fine but need a little more input from the photographer.
If the lens has an aperture ring camera control of the aperture will only be possible with the ring in the 'A' position. Otherwise you are setting the aperture to the value on the ring. The earliest K & M series (without an A on the aperture ring) will need green button stop down metering to be done for accurate exposure metering though I've rarely noticed the difference in ignoring this.
Even Pentax lenses predating the K series, using M42 screw mounts can be used with the aid of a simple adapter that sits inside the bayonet. Initially these were sold by Pentax, but I suspect you would now have to get third party ones or buy 2nd hand.

I totally agree, if the definition being used is uncertain it SHOULD be clarified in the competition description before the comp starts.
An example I keep running into is 'macro' which is defined in most places as:
photography where the image is between 1x & 10x on the sensor (or words to a similar effect)
Marketing departments stretched the term to cover close ups where a 6x4 print is lifesize. So If I was setting macro as a condition I would feel it necessary to include the definition as I understand it. If I failed to do that I would have to accept images that didn't meet MY definition as long as they meet with the common misconceptions/alternative definitions.

It doesn't have one. You can have 'still life pictures' or similar if a plural is needed.

The 'Loony 8' rule is more suitable as it's specifically tailored to the moon (& it has a great name). Just as sunny 16 but open up another 2 stops.

FWIW this works at all phases of the moon but isn't right for eclipses, although we didn't get the blood moon here. When heavily eclipsed the light on the moon is over 4000 times dimmer.

That's a good point, but I think I'll need a bit more help than that. Recent e-bay lens purchases have put my camera fund well into the red.

Well I'd certainly consider a 500mm f/2.8 to be a fast lens. At the other end of the FOV range a 10mm f/2.8 is relatively fast too. It's something that varies significantly with focal length.
To me a 50mm f/2 prime feels somewhat slow even though the actual difference from the standard f/1.7 or f/1.8 versions is very minimal.

In case anyone else tries Googling for more detail they were called 'VFC' in the case of the 24mm (VC brings loads of Tamron stabilized 'vibration control' hits).
They also made a 35mm shift lens with variable field curvature.
While they look interesting but not something I'd really have a use for, especially given the price they go for!

The earliest EVFs where quite poor, but they've improved vastly since then. Are you sure you still find them a problem?

For someone who makes his money renting lenses to those who don't have a suitable focal length in the mount they want yes adapters wouldn't be recommended.
Scanning his report I see there's not a single photo & just MTF traces showing the adapted lens isn't technically as prefect. (So what!)

I come from a very different position where I have the lenses I want to adapt (or can get them cheaply) and I might want to use them in a way that's not possible on the original mount such as with a controlled degree of tilt / with 5mm extension / with a sensor that sees different wavelengths (OK this is possible IF I get another body converted, but then I can't see to focus through the viewfinder). From my point of view / personal experience adapting lenses is highly rewarding & very much recommended. At least when done on the right body...