Deborah,
As the others have indicated, use of "Walkie-Talkies" purchased in the U.S. will be illegal in Europe as these use different frequencies (some of the U.S. models operate on EU emergency service frequencies).
Regarding use of Cell phones from US Cellular, these will NOT work in Europe, as according to US Cellular network "We employ Code Division Multiple Access (CDMA) 1X technology on the network system-wide." and that is NOT compatible with the GSM technology that is used by 85% of the world (including Europe).
Based on your situation, it would appear you have two choices:
1.) Agree to meet at a specific spot in the airport. Check This Website for an excellent description of the airport, and also the transportation into the city.
2.) Travel with GSM Cell Phones. You could either purchase two unlocked quad-band GSM Phones from E-Bay and use with a "travel SIM" from Cellular Abroad, Call In Europe, Roam Simple, Mobal, Telestial or other "travel phone providers". You can also rent a phone from these firms. I'd suggest using text messaging rather than voice calls to keep in touch, as it's much less expensive.
As you'll probably be together most of the time after your meeting at the airport, Option 1 would seem like a more logical and cost effective choice. Of course, traveling with at least one Cell phone would also allow you to keep in touch with family back home (again, text would be cheapest).
I was in Paris again in May. If you have any further questions, post another note.
Cheers!