My apologies if this has been asked before (did not see it though) or if it is just obvious that I should know but have a question regarding Germanic Rally.I think you made a typo: "In the Winter, there are two Germanic Tribes and a Roman auxilia and fort in Sugambri." Should probably read "there are two Germanic Warbands" since you say there are no allies
In the Winter, there are two Germanic Tribes and a Roman auxilia and fort in Sugambri. There are no allies in either Sugambri or Suebi (North) so there is No Control for the region. The first bullet of the Germanic Rally says to place as many Allies as possible. None can be placed in this region since there is no control. Next bullet says to Rally and place as many Germanic Warbands as possible. Since there are no allies I can only place one Warbands. This now gives three Germanic Warbands to the two Roman units so control is given now to the Germans. My question is do I now place one ally (at Suebi?) since there is now Germanic control or has that past and I now move on to March?
Regardless, the question boils down to "do you go back to a previous step in the instructions" and the answer to that is no.
Germanic warbands are only placed after you are done checking for and placing Germanic allies. Once you are done checking for German allies you do not go back to that step of the winter phase until the next winter or if instructed by an event.