I would err on the side of caution regarding sa offer sayo. Clear naman sa AHPRA na as of the moment 2 lang ang pathway to be an RN here in Au. One is the bridging program which is to be phased out in favor of OBA and the other is nursing conversion course and lest I am wrong, it is a diploma course and not classified as VET.
Wala namang problem with regard to bringing a dependent, however, advisable na ma-approve muna si main applicant tapos subsequent na lang si dependent dahil baka ma-delay ang approval o ma-deny kung may magiging problem like case of dependent failing in medical exams.
As to being able for you to both work and support your stay and studies, it depends on lots of factors, lifestyle, employment opportunities na malapit sa inyo, employability, etc.... Even PRs have some difficulty with finding jobs these days.
Technically, tama naman si agency na ok lang less than 3 years experience, afterall, recency of practice requirement requires only 450 hours or experience within the past 5 years. That's only about 3 months full time.
As to your points for immigration, I would suggest you check for avenues to increase it. While 65 is the minimum, bear in mind that the Skilled Migration pathway is by invitation (by the Commonwealth (subclass 189) or State (subclass 190), Regional (subclass 489). The invitation is points-biased, meaning that those with higher points get invited faster. It's a different ball-game if employer-sponsored/nominated (subclass 186).
Hope this helps.