Yes, you can do that. I don't tend to use many finings (as they do usually impact the flavor of the wine, even if slight), so I'd try cold stabilization first just to see if that helps first.
Isinglass is positively charged, meaning it would remove negatively charged hazes (like tannin and yeast). Since it didn't clear, I would assume you have a positively charged haze then. Perhaps protein. If that is the case, a negatively charged fining would be the fix.