If 10 people gathered for a minyan for the repetition of the amida, but 10 were NOT present for the silent Amida - may a repetition with kedusha be recited or not?
Refer to O.C. 69:1. The starting rule is that there were a group of people that didn't hear Kedusha (among other items, irrelevant to your question). It says that one person says Avot, Gevurot and Kedusha assuming that there are now at least 10 people (which is your case.) See the remainder of the paragraph that elaborates that even though you now have 10, at least 6 of them should not have heard Kedusha, previously (I guess this prevents extras that come in to form the minyan but had heard it in a different minyan?)
Also refer to Mishna Berurah commentaries 8 and 9 which elaborate further and offer other opinions.