US Immigration from Romania

Hey everyone. My fiancee recently got her K1 visa. She and her parents are coming to the states in a few hours, but there was a problem with the flight. According to the airline, they cannot travel to the states with a stop in the Shengen zone. Scrambling, I was able to contact my travel agent to get re-routed flights through Turkey. Will they have any problems at Imaginations with there visas? Does anyone have any information about this?

P.S. Her parents have tourist visas.

My wife filed her I751 and got a 18-month extension letter for her Green Card. However, the case is still pending and the 18 months are coming up in January 2021.

Not being sure if her case will be completed by then, especially with delays due to COVID, wanted to be proactive and request another such letter providing an additional extension. For anyone who s been through this process, would greatly appreciate if you could tell me how to go about it.

Not sure if it ll help, but she has also filed the N400 in April for the meantime, but not expecting that ll before January either.