Here, I’ll help you edit your statement:
“The Confession of Dositheos says clearly that souls only go to Heaven
after the Second Coming. Also, the word Hell is
never mentioned in the document. Hence, it in
no way says that all souls go either to Heaven, Hell, or Hades immediately after death.”
You should have read it more closely.
You misread that quote you gave about “All that
after the coming of Christ the Saviour would enter into the Kingdom of the Heavens must be regenerated.”, it is actually lifted directly out of the documents of Trent. This quote is saying the manner of forgiveness of sins through Baptismal Regeneration is
now required ever since Christ came and instituted it, where as before Christ came sacramental Baptism was not required.
You forgot about
post 18, in which you quote me, quoting decree 18?
We believe that
the souls of those that have fallen asleep are either at rest or in torment, according to what each has done; — for when they are separated from their bodies,
they depart immediately either to joy, or to sorrow and lamentation; though confessedly neither their enjoyment nor condemnation are complete. For after the common resurrection, when the soul shall be united with the body, with which it had behaved itself well or ill, each shall receive the completion of either enjoyment or of condemnation.
This quote is easily seen as taken from Florence and Trent. The “rest/joy” is Heaven, and the “torment/sorrow” is Hell, even if the terms are not used. It says nothing about this being a probationary period in Hades until the common resurrection. The Catholic Church fully agrees that the joy/condemnation don’t receive their full measure until the bodies are reunited, but that is not the same as not being in heaven or hell IMMEDIATELY upon death.
THEN, the VERY next paragraph says this:
And the souls of those involved in mortal sins [Latin terminology/concept],
who have not departed in despair but while still living in the body, though without bringing forth any fruits of repentance, have repented — by pouring forth tears, by kneeling while watching in prayers, by afflicting themselves, by relieving the poor, and finally by showing forth by their works their love towards God and their neighbor, and which the Catholic Church has from the beginning rightly called satisfaction [Latin terminology] — **[their souls] depart into Hades, and there endure the punishment due to the sins they have committed. But they are aware of their future release from there, and are delivered by the Supreme Goodness, through the prayers of the Priests, and the good works which the relatives of each do for their Departed; especially the unbloody Sacrifice [Latin terminology] benefiting the most; **which each offers particularly for his relatives that have fallen asleep, and which the Catholic and Apostolic Church offers daily for all alike. Of course, it is understood that we do not know the time of their release. We know and believe that there is deliverance for such from their direful condition, and that before the common resurrection and judgment, but when we know not.
This is likewise lifted directly from the documents of Trent. The only difference is Catholics don’t formally use the tern “Hades,” the concept is identical however, and that is because it comes from a Catholic document. These are the only group said to be sent to Hades. So my point stands.
Also, in the quote you gave, it clearly and explicitly says infants require baptism to obtain remission of original sin, thus they are born “un-saved”, lacking something, and this is precisely what the term “guilt” in Original Sin signifies. (and this concept is one in which many EO I have consulted would be repulsed by as a Latin invention, foreign to Orthodoxy)