Fra Angelico was Italian, so it is probable that the picture represents Italian instruments rather than Irish ones.

Of the two players in the upper left of the picture, one is playing a drum with jingles, using the hand - probably a tamburello . The other is playing a snare drum, using a stick on the snare side - characteristics of a tabor .

In the lower right, there is another tamburello player and another tabor player (again the snare is clearly visible), this time also with a pipe which is a common combination.

One thing is sure - they are not bodhrans, which apart from coming from the wrong country only started to be used to accompany music quite recently (although what the Irish were playing in the 15th Century is anyone's guess)