Ryan, thanks for this. It’s a very interesting interpretation. Here are some initial thoughts:

• It’s not clear that there are two figures in Micah 2:13. It looks to me rather as though the one who breaks out or breaks through is the same as the king who passes on before them, who is also ‘the Lord at their head’. The allusion only really works if the figure breaking through the wall is John the Baptist leading others (the biastai) who break through after him. But it is then a problem if in Micah it is the king who breaks through.
• The Hebrew פרץ seems usually to have the rather specific sense of breaching a wall. It is translated by biazomai in the LXX of 2 Sam. 13:25, 27, but here the specific sense appears to be missing. (Both words also occur in Ex. 19:24 but not as equivalents. In 2 Macc. 14:41 biazomai has the sense of breaking down a door.) So it’s a little odd that we have biazomai / biastēs in the Gospels. Possibly they are meant only to capture the general idea, but then we have only a very slight literary link with the Micah passage.
• Nothing in Jesus’ words overtly suggests the sheep-shepherd metaphor.
• I’m not sure your translation really does justice to the Greek of Matt. 11:12. The whole thing is horribly complex, but I don’t really see, for example, how the ‘kingdom of heaven’ would be the subject of biazetai if in the background is the metaphor of either a shepherd or his sheep breaking through the wall of the fold.

I’m not sure that any of these observations absolutely discounts the association with Micah 2:12-13 - it’s certainly a very attractive idea. But my feeling is it remains rather tenuous. Not that I have anything better!