Taanit #4 Summary of sections 1-3

Before we proceed let us clearly formulate the core of our issues. In essence, Rambam's presentation of Hilchot Taanit seems to lack any coherence. This incoherence is to be found at multiple levels:

a) "Hilchot taaniyot":
The name "Hilchot taaniyot" indicates that the central theme or framework should,in fact, be taanit. This expectation is immediately dashed, the framework is said to be teshuva. Taanit is not even mentioned as a primary instrument of teshuva in the first three halachot. The only instruments mentioned there are zaaka and trumpets.

b) Baal Peh vs Bichtav
While, in baal peh, the primary instrument of teshuva is said to be zaaka, in bichtav it is said to be trumpets.
10:9 When you go to war in your land against the adversary who oppresses you, then you shall sound a teruah with the trumpets.

Another difference between baal peh and bichtav is that in Baal peh trumpets are presented, primarily, as instruments of teshuva, in Bichtav trumpets are only secondarily instruments of teshuva, they are primarily presented as practical communication devices of Moshe Rabbenu.
10:2 “Make two trumpets of silver. You shall make them of beaten work. You shall use them for the calling of the congregation, and for the journeying of the camps.

c) Taanit vs Teshuva
In taanit the primary intrument of teshuva is zaaka or trumpeting. In hilchot teshuva the instrument is vidui.

Where are we to find guidance from this perplexity?