I would, of course, take the 1hr 40 connection at BWI. It is a very low stress airport compared to JFK or something like that. My kids are 1, 3, and 5 and frankly the only holdup we have on international and/or widebody flights is waiting for the stroller to appear. My kids are very experienced travelers though who are used to 35-40 minute domestic connections. Personally with 1hr 40mins, I think you'd even have time to grab some Chick-fil-A at BWI before your connection. If for some reason you miss your connection, you will most likely be accommodated on the next one. Nothing more painful in an airport than sitting there with cranky kids watching the earlier flight to RDU take off without you so that you can catch your 10:30pm flight an hour from now.