>> May I also ask: what is the purpose, at least in my example that I'm learning from, of:
>> \definefontfeature[arabic][default][mode=node,script=arabic] ?
>> 
>> I ask, because when I switched it from [default][default] to [arabic][default] as you suggested, the Arabic glyphs no longer connected, and the text actually spilled over into the footnote space. When I commented it out, the glyphs connected again.
> 
> With my setting you create a new font feature ”arabic” which inherits the setting from the ”default” features with the extra settings “mode=node” and ”script=arabic” while your settings extends the ”default” features with these values. I did this because you use the ”arabic” font feature in the \definemainfontfallback setup but i forgot that context already has a “arabic” feature which enables a lot of font options which you need.

So, in light of what you and Khaled have mentioned, I suppose I can remove that line, and simply use:
\setmainfontfallback[Lotus Linotype][scale=1.33,features=arabic,range={arabic,arabicpresentationformsa,arabicpresentationformsb,arabicsupplement}]


>> Finally, so that I can start learning on my own without bothering you and everyone else on the list, where would I have systematically found a discussion of RtL feaures such as rule=right?
> 
> Maybe in the list archive but often such things are discussed offline, i found it myself in the source.

Scouring the source is rather intimidating at this stage. I guess that at least partially justifies my sending questions on here, since I haven't seen r2l mentioned anywhere else at all. ;-)

>> Or are there any preexisting example files of complicated Arabic that I could study and learn from?
> I guess the wiki page you already know is currently the only source.

Yes, I'm looking for more real-world, detailed examples, to study and mould my own document off of. In any case, once I'm more self-confident, maybe I can do my bit and add some of this info onto the wiki.

Thank you for all of your time and help.

Kind regards,
Talal