First, congratulations to your offers!
I am a first year PhD at UW Biostats now. I'd like to provide you with something I know.
In my year, there are 5 masters and 2 out of them are funded now (1 for TA and 1 for RA). The guy who is doing RA once told me that he contacted one of the professors and after several talks he got that position. I don't know how another guy got his TA.
I guess the likelihood of you getting funded depends on how many PhD at last enrolled in this year. First-year PhD students have priority to get funded for sure.
As for the PhD pathway you mentioned, I am sorry that I am not quite familiar with this part. I don't know any 2nd-year or 3rd-year PhD student here who was first admitted to our master program then got into our PhD program. You'd better to ask this from department directly.
Hope this is useful.