PsyDuck90

No one can tell you how your parents will respond, as that's entirely dependant on their personalities. Based on your mother's comment of the world doesn't need anymore psychologists, she may not understand the extent of what psychologists can do. You just have to come out and tell them. They'll figure it out soon enough when you start applying for programs. My advice would be to just outline to them exactly what you wrote in this post:  OT doesn't excite you, you've been working in a psych research lab, and you want to switch trajectories. After all, that's part of what undergrad is all about. 

The APPIC website has the stats. 

The best advice that I can think of is to look at the researchers publishing within your field of interest and seeing what universities they are affiliated with. If your ultimate goal is PhD and you really want to get the master's first, then you want to be in a lab that is within your area of interest. Clinical programs still heavily look at your research experience, including posters and publications, and you could potentially bolster that more through the master's program. 

I'm only in my 1st cycle, but the POI in my top choice program told me that they wished they could've extended me an interview invite and stated I should apply again next year if I don't enter a program this fall. I'm assuming not all programs operate like this, but given the low acceptance rate, many schools understand the importance of persistence. You could be an ideal candidate, but so can 2 other people, and all of you are vying for 1 or 2 spots.