You can get in-line shutoff valves for the 1/2" main or the small lines. Set up a "backbone" with t-fittings and have the watering lines coming off the with the shutoffs and then the emitters.

But there aren't any plug/unplug fittings I have found.

Hmm. I know that hot water will loosen things, but I've kind of assumed that any water hot enough to free an in-line emitter would probably damage the emitter.

Maybe hot water on t's is safe.

For what it's worth the red emitters work fine in "off" position (from testing just one) and seem to start at about 1/4 gal per hour (by inexperienced eye).

So maybe I'll set up a backbone with a bunch of those hanging off ...

They were called "UN3F 50pcs Micro Flow Dripper Drip Head 1/4 Inch Hose Garden Irrigation Misting" and were just $4.47 for 50, free shipping.

Lazygardens suggestion to have a backbone is correct. From that, an indivual line to each pot is your best solution. An adjustable sprayer/drip emmitter lets you control flow and shut it off completely if necessary. This will also improve your waterflow to each pot. You can also have multiple branches off the backbone and use an inline shutoff valve like this one.

Here is a link that might be useful: Inline 1/4

Lowes sells for a very fair price "universal" fittings that have a cap that slips over the hose and tightens down over it away from the center of the fitting.

I didn't describe that very well but they're easy to remove and reinstall.