There's some missing details here, are you planning on marrying a Taiwanese citizen? Are you getting married here in Taiwan? Because, that sounds almost like what you're describing.
I went through that process nearly 6 months ago. You're thinking of a visitor visa, under the condition of "visiting family," which can then be changed to a JFRV. Since I came here under visa exempt status and surprised my wife by asking the question when I arrived, next came the painful process of getting married and obtaining a dependant ARC here.
My laziness just kicked in. But I'll touch on this, I'm not married in the US yet so I had to prove my single status here. It involved raising my hand and saying, "Yeah I'm single," then paying like $600 NTD. The FBI background check took a long time to get, even with expedited service.
Anything I'm missing?