The chances of you having a problem using a Zip-Loc or some similar container are very low, in my opinion. I suppose if one of your drugs is a narcotic that's susceptible to abuse, that could be an issue and perhaps that should be prioritized for the "original container" treatment.
When I lived in the states and had an extended visit to Europe, I just dumped them all loose in a Zip-Loc bag and carried a photocopy of my prescription. Despite having a bag with several dozen random pills in it, no questions were asked.
I think part of the original container stuff may originate with how prescription pills are dispensed in France. Pretty much without exception, they're not in a bottle but in a box that contains several bubble packs, one pill per bubble, perhaps 20 or so bubbles per pack. The back side of the bubble pack is printed with the name and dosage per pill of the drug each bubble contains. In the (highly unlikely) event someone wanted to check the drug and dosage against a prescription, the information on the bubble pack likely would suffice. As a practical matter, some physicians in France still hand-write prescriptions and no one but the local pharmacist, who has learned how to decode the hieroglyphs this particular physician uses, can read it. A random person at an airport check station wouldn't stand a chance. Maybe that's why they don't bother.