Unless you are traveling at an exceedingly unpopular date and time - is there a 6AM Sunday flight Dallas-Fargo? - there won't be five seats together for you to select at check-in. Expect to find middle seats, and some sporadic window seats near the back. The primary point of Basic Economy fares is to get people to pay for things they value. Don't buy basic Economy fares and come back here to complain that you couldn't sit with your young children. You won't find much sympathy. Basic Economy is a choice you make.