Personally, i do this with frozen foods which i de-frost, i.e. Scallops, Mussels, Market Prawns etc... the main reason for this is because imo these foods absorb a lot more of the meds compared to the things you listed... especially since when my puffers see these foods it literally takes them about 3-5 seconds for them to start munching it, and about 10 seconds before its demolished...
Although with that being said, if you can get a syringe to inject the meds into an earthworm that might work even better than my method...
I would probably not bother soaking the bloodworms, since it would more than likely get quite diluted by the time the puff eats it, especially if its sitting in the tank for a little while...
Either way, you could wait for other members to see what methods they use to see which works best... since this is just what i've done in the past...