I would say they can be defined but have yet been done so. The Trinity was understood and even experienced in the early church as seen in Paul's benediction in (2 Cor 13:14). It was finally defined when the Creed was produced in the 4th century. So if Arius never taught his heresy, or if the empire was still persecuting christians it still would not have been defined when it was.
Ath were basically forgotten until Fr. Seraphim Rose. They were more mentioned in monastic literature. Since then bishops such as Met. Hierotheos has tried to streamline their teaching, so the avergae layman can grasp the concept. For example the Russian accounts had some overly sensationalistic aspects which the greeks rejected. No Russian (that i know of anyway) has ever objected to this censure, hence some consensus has been reached(namely saints and holy people are totally unaffected by tollhouses and they ascend to God the demons fleeing from their presence finding nothing in them)
In the end of the day tollhouses and demons as tax gatherers is nothnig more than what St. Gregory of Nyssa taught. That once the sinful soul departs from the body it can no longer act through its bodily senses to appease its passions. But the soul having melded these sinful inclinations within itself will gravitate like to like. So the natural part of the soul made in the image and likeness of God struggles to free itself from the vices towards God, but the passions push it in the opposite direction towards its kindred in Hades. If the soul cannot amputate these sinful desires which are attracting it to the dark side it will remain in that abode forever, scripture calls this kolasis aionon (punishment everlasting).
If it can prune and amputate and cut off and pluck off its sinful attraction for the darkside it will be free but costly as scripture says:
Agree with your adversary quickly, while you are on the way with him, lest your adversary deliver you to the judge, the judge hand you over to the officer, and you be thrown into prison. 26 Assuredly, I say to you, you will by no means get out of there till you have paid the last penny.(Matt 5.25-26
And from the Didache:
Ch1....Woe to him who receives; for if one receives who has need, he is guiltless; but he who receives not having need shall pay the penalty, why he received and for what. And coming into confinement, he shall be examined concerning the things which he has done, and he shall not escape from there until he pays back the last penny. And also concerning this, it has been said, Let your alms sweat in your hands, until you know to whom you should give.
ch3..Rather, be meek, since the meek shall inherit the earth. Be long-suffering and pitiful and guileless and gentle and good and always trembling at the words which you have heard. You shall not exalt yourself, nor give over-confidence to your soul. Your soul shall not be joined with lofty ones, but with just and lowly ones shall it have its intercourse. Accept whatever happens to you as good, knowing that apart from God nothing comes to pass.
So from the above we get an idea why they are called tax collectors and toll houses, they want to extract everything out of you, every penny you owe them for they believe you are rightfully theirs.. If your soul is inclined towards vice it will have intercourse and company with alike (whether demons, other souls, dark places, Hades, inglorious elements etc). And the energy the natural part of the soul requires to pull away from your passions is high, It will (pay out) tenfold.. They are attracted to you finding a kindred in the same passions you enjoy, but just like that clingy friend he will keep extracting everything until you excise them from your soul, or should we say overcome your addictive vices and head for freedom.