You guys are reading way way too much into this. History has already shown the likely outcomes. Two main points.
1. Any independence talk is not going to be on the table. Everyone knows that is the red line, even the more extreme of the anti-China politicians know this.
Look at the history, in mid 90’s-early 00’s, ROC had qualitative advantage over PRC military. They never declared independence. Strategically speaking, that was probably the best opportunity, no carriers, no AESA radars, Russian export Su-27/30, Luhu DDG was still backbone of the PLAN.
HK has no military at all. Would a politician really be that daring to do something like that? It would put so many lives at risk and I really do not think there is a plurality of support anyway.
On top of that, does any HK politician with half a brain really believe west would help them? They let a relatively weakened Russian army waltz into Crimea with only some peeps.
2. Winning an election is the easy part. You can promise the world, but it’s another thing to deliver on it. Obama and peace, May and Brexit, etc.
Will these people handle their constituents local concerns, or will they waste their time chasing political goals?
Nationalist/Independence parties rarely deliver on this front. Using ROC again as an example, DPP never sustains long term success because their ideas of disengagement from PRC are unrealistic and always weighs down the economy.
For HK this is even more unrealistic. Honestly, if a pro-independence politician could totally separate HK’s economy from mainland and actually grow it, they are a genius and deserves the support. (Yes, sarcasm)