I have the first reel of the feature Stagecoach, could the 400 ft digest be edited with the first reel of the feature, to make a longer digest, as I do not know the content of the 400 footer, can any-one enlighten me.

Good question, but be careful, as a lot of these 400' cutdowns can just be the last reel from the feature with a main title,
Mountain films were past masters at that one.