Hello Sunflower,
I agree with the eucalyptus and rosemary essential oils (tea tree oil, clove bud oil and/or oregano essential oils also), and want to add that if you don't already have a cold-mist humidifier, or if it's already too humid where you live, just put the essential oils on a cosmetic cotton pad and tuck it into the grate on the front of a fan. The oils disseminate into the room as the fan runs; the children may find the fan noise relaxing (and therefore help sleep), and as their noses clear, they may enjoy the aroma. The tea tree oil is quite affordable at Trader Joe's, but you'll need to go to Whole Paycheck - er, Whole Foods - to get most of the other essential oils.
As for OTC medicines, for toddlers through adults, I recommend "Old Indian Wild Cherry Bark Syrup". It's an immune system builder and will help "cure what ails ya". You can find it at Whole Foods and sometimes at better-stocked chain drug stores. If you can't find it, look for something with a significant amount of elderberry extract in it. Also if you're not already supplementing with zinc, get some palatable zinc supplement (liquid versions are available for children and lozenges for adults). Zinc will shorten your illness and boost your immunity.
I didn't see anyone recommend vitamin D supplements, so I'll add that in here as well. Supplement at 35 IU per pound of body weight (I think I read that at mercola.com). Vitamin D, zinc and elderberry will help you conquer most anything you might catch in ordinary circumstances.
I also agree that the snot sucker is immediately effective for relief so sleep can happen. I also know how much energy can be wasted resisting it. The nasal saline is also good, but read the ingredients carefully because some of the preservatives they put in the saline are best avoided. I recommend a "neti pot", which looks like a small tea pot, with a nostril-sized spout. You mix your own saline at home (salt and/or baking soda and water), fill the neti pot, stick the spout in one nostril and tilt your head so it's level with your ear down. The saline will run through your nose and sinuses and out the other side. Do the same in the other direction then blow out the remaining moisture. The neti pot is much more effective and more comfortable to use in my experience than the sprays which go up the nose. Perhaps if you let your twins watch as you do the neti pot, they may want to try it out. Particularly if you make it look like fun, or just joke about how you look funny with a teapot up your nose LOL :-)
I'll send my best your way; sick twins are a challenge any day, but especially when you're ill as well. Get well soon!
Best wishes,
Cathi B.