>>259424
>what are the theological differences between Catholicism and Eastern Orthodoxy I should know about?
Catholicism uses Anselmian satisfaction theology, where sin is considered a debt to God that must be payed off, and Christ was crucified in order to pay off Adam's debt, and from this you get all sorts of retarded shit like indulgences and such. Orthodoxy considers sin to be a disease, a parasite that eats away at the soul, which can be healed through fasting, penitence and prayer, and views Christ's Crucifixion as a victory over the powers of Hades and death, not as a solemn affair to sacrifice an atonement to God. Besides that, Catholicism tends to be more intellectual in nature, whereas Orthodoxy tends to be more spiritual and mystical in nature. In Catholicism, a great saint would be considered a preeminent theologian with many intellectual works under his name, in Orthodoxy, an old Russian Babushka who's lived a simple life of prayer and penitence. There's a vast world of differences that it would be difficult to get into here.
>>259424
>Is conversion feasible even though I am already bapthized?
Obviously. It is never too late.
>Do I have to relinquish my bapthism?
You will most likely have to rebaptized, in Orthodox baptize in the traditional way, through full triple immersion, whereas Catholics just sprinkle water on someone's head.
>Do all orthodox liturgies use traditional Latin chants?
Orthodoxy does not use Latin. They use the Liturgies written by St. John Chrysostom and St. Basil the Great in antiquity. If you mean chant, all Orthodox music is vocal and chant, no instruments.
>Is there any important orthodox theologian I should read about
If you're looking for a good introductory book, ID recommend Frederica Matthewes-Green's Welcome o the Orthodox Church.