This side of heaven, missiology and ecclesiology are so intertwined, it is difficult to to determine which came first. Might it be that the sequence is irrelevant, that missiology does not serve ecclesiology and ecclesiology does not serve missiology?
I have said in a previous post that theology proper is the only primary theological element:
On any given day and in any given circumstance, the individual elements relate to one another, sometimes as influence, but always with reciprocation. This means, for example, that missiology does not come before or after ecclesiology, but that these are in a reciprocal relationship, where each influences the other. Depending on the specific need, one or the other has more influence.