<<"I would strongly recommend planning the journey using the interactive
online timetable to avoid any unexpected surprises that might ruin your
day because you didn't fully understand the features and/or limitations
of a particular mode of transport or time of departure :-)">>
That is certainly a good recommendation, until you know the rail network well.
I have been using the timetable since 1980, have some knowledge of German, and still have that problem.
Sometimes I miss the symbol for a bus, and look at the wrong side of a station building. I have done it enough now, that if I can't find a departure on the yellow train departure board, but which shows on a page that I have temporarily cut out of the Kursbuch to carry in my pocket, I automatically look for the bus stop positions near the train station. Thanks the links that you provided, I'll not have to do that any more, as long as I can access a printer.
And, often, I miss the code for days of the week in the time table book. Or, the numbered footnote which explains days of non-operation or of operation.
Your cautions are well founded.
That said, having all the information on one page is very helpful for getting a sense of options.
Detailed planning is probably best done as you say, especially, since you can get a map for any journey from the option in the footnotes. A map is quite necessary, in my opinion.
Another choice is to use Mapsearch.CH, which can show all stations if you work the menus properly.