[quote=@Holmishire]
All of them read grammatically to me. The eighth one is tricky, on a first read-through it fails but as I begin to parse it I can bring myself to read it naturally. The other five are 100% good in my books.
[/quote]

Believe it or not, even I did. I still do unless I have the brackets for (8). I believe in my syntax I class we decided CP specs with CP specs nested in them aren't grammatical, but the field is more open in this course so I decided to craft one. You can probably ellide one of those 'thats' and then it'll sound more natural.