Are there any special considerations that I should employ when creating/editing htaccess with PHP, or is it no different than handling plain text files?
No different except that a single mistake could shut down the site.
And I hope you’re referring to htaccess files for the public facing directories only, not the one that’s usually on the root of the site.
The htaccess file I would be creating/editing would be for the root of the site.
What I’ll probably do is open it, read it, perform all the string manipulations I need to, then write it back.
As a side note, wordpress writes to the root htaccess file. I was just never clear on if they did anything special beyond what I just mentioned.