I can't answer your questions exactly, but hopefully this information will be of some help, or at least send you in the right direction.
Using another Bible software (since I'm still less knowledgeable regarding Accordance for searches / statistics of these kinds), I found that The Michigan-Claremont text (a coding of the Biblia Hebraica Stuttgartensia) has a "Wordlist" of 39,987 words, while the Leiden Peshitta critical edition reports a "Wordlist" of 37,545 for Genesis to Malachi (39 books, and excluding the 19 non-canonical books to make for an apples-to-apples comparison).
If you include the additional 19 deuterocanonical / pseudepigraphical works, the Leiden Peshitta's "Wordlist" comes to 46,530, but of course, this is no longer apples-to-apples with the BHS text I analyzed.
I'm not exactly sure what "Wordlist" means here. I know it isn't the total number of words in the sense of strings of characters separated by whitespaces, since the BHS has over 400,000 "words" in that sense. But I'm also not sure if the 8,769 Hebrew words you mentioned before are strictly "lexemes" or else possibly "lemmas." Maybe you or someone else here knows.
I also hate to have to caution that my analysis of "Wordlists" above may not be so truly apples-to-apples, based on the program I used, because the BHS text is tagged, and the Leiden Peshitta isn't tagged. The program may perform the analysis different depending on whether a text is tagged or not. (I'm almost positive that Accordance would as well).
But if I may gander a guess, I would guess that the Leiden Peshitta would have less individual lexemes than the Hebrew Bible, only based on my experience with both the Peshitta Tanakh (as I call it - "OT"), and the Peshitta Apostolic Writings ("NT"). And, of course, the little analysis I reported for you above.
We know that Hebrew is a far more simplified language than Greek, for example; and Aramaic (for biblical text) may be slightly even more simplified.
For instance, while the Hebrew Tanakh uses a variety of "legal terms" for various precepts in the Torah of Moses (e.g. torot, mitsvot, chuqqim, mishpatim), the Peshitta seems to condense these in translation to the word puqdana. Yes, the Peshitta has words for "Torah" (namusa), "mishpatim" (diyna), but sometimes I think the Peshitta's vocabulary / wordstock is slightly more condensed than the Hebrew Bible (and again, significantly more condensed than the Greek).
Also, just as a point of clarification: Codex Ambrosianus and the Leiden Peshitta Tanakh are not synonymous (since you mentioned them both). Codex Ambrosianus was one of the manuscripts used in the Leiden critical edition, but not the only one. I don't think Codex Ambrosianus has ever been digitized and made available to the public (though you can get it in pdf form online), but it is the Leiden critical edition of the Peshitta that Bible software companies use.
Also, I'm not aware that Codex Ambrosianus has ever been digitized--that is, made available publicly.
Edited by TYA, 06 June 2019 - 11:22 PM.