I don't agree. Your examples are needlessly complicated.
Interested in Language
Suppose we list the number of forms to fill out. Is it possible to say "to be filled out is a form X ...." instead of saying "Form X .... needs to be filled out". This infinitive structure is fronted and is similar to "Joining me in the studio is Frank, which expresses "Frank is joining me in the studio" or "I am joined in the studio by Frank".
Do you agree with my "to be filled out is a form" infinitive structure"?
Instructions should preferably be in the active, and not passive voice and in the imperative. E.g. "Fill in the following forms: Form X, ...
Your examples about "Frank joining you in the studio" does not involve the infinitive.
I am not a teacher.
No, it doesn't but both "Fill in the following forms: Form X, ..." and "Joining me in the studio is Frank" are examples of fronting (removing something from within a sentence and placing it at the front of a sentence).