Oil is a big problem in silicone. Learned a great tip here - use old visine bottles for oils (I never knew the tops could be unscrewed!!) So if you use face oils - easy to take a tiny bit with you.
Instead of contact lens cases, I typically reuse small screw top sample cases (eg the kind Nordstrom gives out) for small amounts of eye or face cream or first aid cream or whatever.
And I just use a ziploc. Though if I am checking bags and pack liquids, I have a larger waterproof bag I'll pack in. And if I'm bringing liquor or wine, I'll vacuum seal before padding, just as an extra layer of protection...