Nope, because in the sentence '몇 명을', the 을 makes people the object, meaning that someone or something is meeting the people. For your sentence, it would work if you said 몇 명이, cuz the 이 would make people the subject, meaning they would be doing the meeting (instead of people being the object where someone or something is meeting the people). Hopefully that makes sense.
We've been told in Korean it is common to omit understood pronouns. Perhaps when they want to emphasize your concept instead, they add words like the few we learned for 'together' or change the ending of the verb? With the lack of context in these exercises, I try to look for these types of patterns in each lesson.