Auxiliary standards

[Robert Vermaat]

However, as I have discussed in a previous post, my assertion is that the Draco standards were all purple in colour and appear to have perhaps been a symbolism of the Emperor, even if he were not present, much the same as the Eagles were the representation of the might of the Legiones.

I know you did, but apart from some sources who describe that the draco of the emperor was 'purple' 9and see my earlier post), there is no source who confirms that
a) all dracos had a 'purple' tail or
b) all dracos were to be compared to the eagle
Eagles were never the symbol of the emperor, so why would a draco be that? Plus, if every cohort had a draco, how could we even compare that to the eagle in terms of symbolism?