Who can help me to choose the correct word.Sometimes both are possible:

1.We could/ we were allowed to interview her yesterday.( for me both seem acceptable)
2.I lost my key but I could /managed to climb in through the window.(managed to climb or both are correct?)
3.I tried to start the car but I couldn’t /didn’t manage to.( both ,in my humble opinion)
4.I was able to /could meet him last Friday.(was able to -or both are correct)
5.They said we could /were able to stay.(could -the correct one)

Thank you!