  Recent advances in electron spin resonance techniques have allowed the
manipulation of the spin of individual atoms, making magnetic atomic chains on
superconducting hosts one of the most promising platform where topological
superconductivity can be engineered. Motivated by this progress, we provide a
detailed, quantitative description of the effects of manipulating spins in
realistic nanowires by applying a first-principles-based computational approach
to a recent experiment: an iron chain deposited on top of Au/Nb
heterostructure. As a continuation of the first part of the paper
experimentally relevant computational experiments are performed in spin spiral
chains that shed light on several concerns about practical applications and add
new aspects to the interpretation of recent experiments. We explore the
stability of topological zero energy states, the formation and distinction of
topologically trivial and non-trivial zero energy edge states, the effect of
local changes in the exchange fields, the emergence of topological
fragmentation, and the shift of Majorana Zero Modes along the superconducting
nanowires opening avenues toward the implementation of a braiding operation.
