Ne is used to replace a direct object noun modified by a number indicating quantity (among other uses). The translation above actually leaves out the meaning of "ne". It could be translated as "she has received seven of them in total" Ne represents "of them" in the sentence, and would replace a previously mentioned noun. As with the use of direct object pronouns with the passato prossimo, the past participle agrees in number and gender with the object. Since the ending for the past participle is "i" ("ricevuti"), I would believe that the object represented by "ne" was masculine.
I do not, however see anything in this sentence that would indicate that the subject was a "she" rather than a "he".
I put "He has received seven of them in total" and it was accepted. So I don't think there's anything specifically stating it's a 'she'. And it took the added "of them". I was proud I got that one too, since it's been really hard to wrap my head around 'ne'! I lived in Italy for a couple years and I swear I don't remember anyone ever using 'ne'...I'm convinced it's a duolingo conspiracy! :)
It's related to the 'ne' which is basically 'of them' as in 'seven of them' and since there were seven of them that were received, then it's plural and thus ricevuti (plural form) not ricevuto (singular). While the past participle normally stays in the ricevuto or basic form with ha, because it's got the Ne in front of it it doesn't, it agrees with the pronoun before tha 'ha'
It might be an accurate interpretation, but at least in English these two translations imply a subtle difference. Saying that someone received seven of them "in total" simply indicates how many were received altogether without implying how many could or should have been received. Saying someone received "all seven of them" indicates that there were only seven, and all of them were received. Probably not a big or meaningful distinction in day-to-day conversation, but to me, at least, there is a difference.
No, "ha" has nothing to do with "ne". ho = I have, ha = he/she/it has. "ne" is a particle that replaces a noun that has been used earlier. A good explanation can be found in https://ciaoitaliablog.wordpress.com/classes/the-italian-ne/ For me, being Dutch, "ne" is not a problem. We use "er" or "ervan", which can be used in many circumstances.