The same website that created a script for text reversal, has since released an After Effects script for Arabic Text specifically.
https://aescripts.com/arabictext/
The regular text reversal did not work for the reasons stated above, but this script actually places the characters in the correct order.
The workflow is a little goofy. For example, if you want to split the text into several lines for a paragraph you kind of have to work backwards through the text. (eg. Hit return X times for your line breaks and then move the ‘end’ of your Arabic text up to the top line.) The program, AE, still operates left to right so editing the text requires some backwards thinking.
However, the end result is fully editable Arabic Text. You can use any font and any text animations. Although, keep in mind that the text animations will animate the lines backwards, from left to right, and I’m not sure what different fonts will do to the characters (“Do they need the serifs or not?”)
The thing about working with graphics in different languages is that having more control can be a dangerous thing. As designers, we want to style the text in a certain way, but the truth is that we don’t know what we’re doing to the meanings of the letters or words so we have to be careful.
John Shoemaker
Backflip Film Productions LLC
http://www.backflipfilms.com