Nice Shots Craig.
2 and 3 from the first batch...
No 2 Lovely light in the clouds and across the range behind, this would also take a letter box crop by taking some of sky away as much as i hate to remove a nice colourful sky.
My only other OCD related comment is the fallen tree in the bottom RH corner, just bugs me a little.
No 3 this is nice, pity the light wasn't fully with you however there is something to be said for the muted light, and those trees in the immediate foreground being softly lit. The singular tree (Birch?) slightly apart and standing front and center is nice.
Nice light though the last 2. In the first of the second series i can see
@ST4 crop, equally you can flip that and crop the top off which is an alternative albeit not as good as the top because of the wayward top of the pine tree right of center at the bottom edge.
Second of the last series, is nice, the side/back lit larch is lovely.
As for the light I would tend to agree, if your tutoring, my view is you should shoot in all lighting conditions for many reasons. Lets face it, if the lights great, then the challenge of getting a great shot is less. Trying to get a great shot in flat light, (Was going to say also peeing with rain and blowing a hooly, but that would be a coastal shooting) that is a challenge!
The challenges associated with taking a good landscape shot with blank and boring landscape and flat light that IMHO is the important thing to learn.
I think learning about light, and composition is probably the most important thing. Its impressive how some photographers handle adverse light and conditions, and were all faced with that often enough.If you have just driven 100 miles and your location is plagued with crap light you need to know how and what to shoot to salvage something.
Just my 2d