This question seems to be about the existential expression THERE + BE. If this is the intention of the sentences--to express existence--Sentences 1-1 and 2-1 are correct, as you say. In addition, Sentence 1-2 is also correct, since it is not ambiguous and its noun has a short complement, "to do by next week."
Sentence 2-2, with the participial phrase "working in your office" right after the noun "people" is different. The construction
"How many people working in your office..."
could lead the hearer to believe (momentarily) that the speaker is talking about a subgroup of a particular group of people, i.e. the people who work in the addressee's office. With this word order, for example, the speaker could go on to say
"...have children of preschool age?"
"...go out after work to socialize?"
"...do you know really well?"
So the word order is confusing. It's not a fatal flaw, but it does not make for effective communication. For clarity, Sentence 1-2 is preferable.