In short, no. One of the major factors that worked against feudal-esque action within the Byzantine Empire was the concept of private property and the efforts of the emperors to curtail the powers of wealthy landholders, as well as the fact that for a good portion of the Empires lifespan there was no such thing as the typical French peasant (Treadgold 317) , but rather the vast majority of farmers were independent land holders which completely negates the seigneurial system that accompanies the Feudal idea.
The primary thing that prevented the growth of a Feudal-like system as seen in Western Europe is private property (Khaszdan, 88). While that might not seem very odd to us today the concept of private property was something of a rarity in the Middle Ages as most land was granted by a lord or by a king, but still theoretically under the king or the lords control. This meant that to become a landed magnate, or in the case of this question a "Dynatoi", the individual must purchase all of the land he owned from freeholding peasants. The land a Dynatoi held was not granted to him under the condition of military services and he was not granted legal powers by the bureaucracy of the Empire; however, This man could still act as the law on his own land simply due to the lack of speedy communication at the time, and in the cases of the later empire the inability of the emperors to contest the wills of the landholders, as more often than not during the later empire the Emperor was simply not strong enough to fight the Magnates over something as trivial as the law.

If however I have misunderstood your question and you want an answer in reference to the Stratagoi who governed the Themes of the empire then yes, they could take both civil and military actions within their respective Themes during the later Empire. In the earlier portion of the Empire the governance of Themes was divided between a civil and military office