It doesn't make any difference whether the direct object is a person or not, except in Sentences 1 and 2. Sentences 3 and 6 both have adjective complements and obey the same rule.
1. I want you [to be] finished within ten minutes.
The infinitive "to be" cannot be omitted. The same idea can be expressed with the perfect infinitive:
"I want you to have finished within ten minutes"
There is no understood passive in these sentences. The meaning of "finished" in this sentence is "through, done [doing something]," as in "Are you finished with the sports section?"
2. I want this [to be] finished within ten minutes.
Either form is OK. The meaning of "finished" here is "completed." It's a passive idea. The version without the infinitive is very strong--a directive. It's like
--I want the toys put away before you go to bed
3. I want you [to be] proud of yourself.
Adjective complement. Both are OK. With the infinitive it's standard; without the infinitive it's informal.
4. I want you [to be] there by 4 o'clock.
Adverbial complement. Both are OK. The version with the infinitive expresses a desire; the version without the infinitive is a directive.
5. I don't want this [to be] an issue between us.
Noun complement. With a noun complement you must have "to be."
6. I want my coffee [to be] black and strong.
Adjective complements. As with Sentence 3, both are OK. With possessive general noun objects that are to be "consumed," the version without the infinitive is more common, for example:
He always wants his eggs runny and his steak rare
(The same occurs with the main verb "like":
--I like my coffee strong and black)
7. I want the papers [to be] on my desk by tomorrow noon.
Adverbial complement. Both versions are OK. The version without "to be" is a directive.
In all cases, the versions with "to be" are much more frequent than those without. That's because the versions without the infinitive are either directives ("I want you there by 4 o'clock") or informal ("I want you proud of yourself"), while the versions with the infinitive are standard. The only exception is with general possessive noun objects that are to be "consumed," as in Sentence 6. In that case the infinitive-less version is more common.