-Can I remelt these as normal, maybe adding a little softener, and a bit of new plastic??
You would only need to add softener / hardener if you wanted to alter the plastic. You may need to add heat stabilizer.
-Will my baits come out relatively normal(like they would with new plastic??
There's no way to know without knowing the brands of plastic you are mixing, not the bait brand, but the brand and formula of plastic the bait company used - and what they may have added to it.
-Is there anyway I can, I don't know, hide/camouflouge/get rid of all the existing glitter that are already in these baits??
Not really, unless you just made them a super dark color.
Is there anything I should be careful of??
If you wanted to be careful you could first try it in small batches.
I would definitely add some new plastic to each batch. Some have had problems with the plastic not being very workable, others have done just fine. I'm sure it depends on the baits being melted. Large bait companies use different formulas than we do, they are engineered specifically for their process. Add it in small quantities to your regular colors over time, test it in smaller batches first.