Rather than asking here, I would start with a visit your public library or bookstore which should have some books that will help. Look at books on wall construction (in order to know what you can fudge on, you need to know about good construction practices) as well as books on rock gardening to know what will benefit the plants. If there is instructional material that come with the wall-building materials, read that as well.

IME in an area with frozen winter soil like yours or mine, you want good drainage behind the wall, especially if you want the walls to be stepping back which will tend to guide water into the walls or if there is natural drainage off something like a hillside. Gravel behind the wall will also discourage the tunneling of voles, chipmunks, etc. which is disruptive to the plants and the wall. I don't know how heavy your building material is (the majority of mine tends to be natural rock that needs a tractor to move) but light weight building material will move more easily. If you are actually holding back soil that slopes up from the wall, there will be more pressure against it than something like a small raised bed. In an area with more clay soils, the wall will move more than in an area with well-drained soil.

I usually put in pockets of soil with small plants and water well the first year. I have had better luck with self-seeding plants (Dicentra eximia is quite happy seeding into walls) and creeping rock garden plants that are happy with good drainage such as the hardiest Campanulas and Chrysanthemum weyrichii.

Thanks, the intent
is to go against the 'book' and build a half-way deteriorated stone wall more like in the pic below
(albeit with better looking plants) and less like the neat wall in pic #1 in
the above. Perhaps I should have posted the pic below in the original posting,
but most blocks are man-made like in pic #2 in the above, they are not heavy, about 7-8 pounds each (I have used it before)

The main issue is how
much I can (deliberately) deteriorate the wall before maintenance becomes
excessive, there is not much to read about that. Perhaps trial and error is OK for this
small project, e.g. if a section quickly falls into ruins, then tighten it up
'according to the book'.

Anyone has tried something similar?