Pectic enzyme breaks up the fruit pectin- that might clear up the wine if you have a pectin haze since you haven't used it yet.
As far as the other things, you can add acid blend or tannin at any time. Acid blend can help a "flabby" wine get some depth by providing some acid, and tannin gives wines a "bite" to them. If you use either, start very very small! Tannin especially can be strong- 1/8 teaspoon is not too little to start with, and even less ideally would be added at first in a small volume. It doesn't dissolve easily, so take a sample of the wine out, stir it in very very well, and add it gently to the rest of the wine (as to not aerate it). The acid blend is best added the same way, so that you don't stir the wine at this point.
I don't normally use clarifiers, but if you have a wine that just won't clear after sitting at least 60 days and is no longer dropping any lees, then you could try.