Realistic answer is that 75 is unlikely but possible, and 76 is only a little bit better. Speaking generally* I mean, obviously your competition will vary from year to year. You may well get in this year, but if not, there's always next year. Mid-year intake is apparently less difficult**, because there's less competition and the people you're competing with are likely people who have previously failed to get in and therefore may not have super competitive WAMs in the first place.
*Based on conversations with law SS, successful law transferees and posts I've seen on AN.
**Based on my own successful transfer with a low-ish WAM + a single conversation with law SS earlier this year.
Wow, this is actually pretty low (in my opinion). It's been ridiculously easy getting HDs in Arts compared to the score needed for entry direct from VCE.
I don't know how many arts units you've done, but your experience is definitely not representative. Of course, getting a credit or distinction in an arts unit is way easier than in some other faculties, but arts units are extremely stingy when it comes to awarding HDs.