You are correct, however, I believe this distinction needs to be made;
A first appearance can very much be a cameo.
Within the collector community, those two distinctions are; 1st appearance in cameo. And 1st appearance in full.
Hence, a cameo is a 1st appearance and a 1st appearance can be a cameo.
For those who read the books, it is obvious that Dylan is in issue #7, and issue #9. No one needs to ask Danny Cotes what comes first, seven or nine? Of course Dylan makes his 1st appearance in #7. But the collecting/reader community decides if said appearance is a ‘cameo’ or a ‘full’ appearance, not the creator. This topic was discussed, at length, on CHU months ago…
…and I posted pics on CHU of Dylans appearances in #7, to see if the community thought that Dylans appearance in #7 was a full or a cameo. Whether that appearance is considered cameo or full is not Danny Cotes’ decision to make. No one individual makes that distinction. It is a collective, unwritten decision made among the community.
Im not so sure that the cameo/full debate is as nefarious as you seem to think it is. ‘Dealers’ did not get together and make IH181 the book to own, the collecting community did. Buyers, not sellers. Many theories can be brought forward as to why 181 is ‘the’ book over 180. Two words. Cover appearance. Wolvie is on the cover of 181, and not 180. And lower print is not always a factor. Eg. Venom clearly makes his 1st named appearance in ASM299. That is the first time we see Venom (pre cates retcon). But, the market has chosen ASM300, w/ its astronomical print run, as ‘the’ book to own for Venom, despite ASM300s massive print and 2nd Venom appearance.