Why did you not include Eastern Orthodox ignorance? They agree with Protestants on much of the things I mentioned. They, like Protestants, are opposed to RCC purgatory, celibacy, priests and nuns (they have patriarchs), etc.
As opposed to this state of affairs we believe, -- both Roman Catholics and the Eastern Orthodox -- that the Protestant dogmatic distinctions from both of us: the belief in the Bible alone as a rule of faith, the believe in salvation accomplished once in one's life time through declarative faith alone, the belief in accidental rather than efficacious nature of the sacraments of the Church (signs without grace) and derived from that anti-clericalism - are all results of ignorance of the Holy Gospel of Jesus Christ and are leading people away from salvation. You, Protestants, should all convert to a true Church, -- Roman Catholic preferably, but if you feel too much hostility in your hearts to this sacred institution, you should then convert to any Orthodox Church and that will put you in the road to salvation just as good as the Roman Catholic Church.
Now that we are clear where these three branches of Christianity stand, let me comment on the particular disciplines you mention.
Purgatory: The Orthodox also pray for the dead and believe that the soul fortunate enough to be saved goes through certain stages, likened in the Orthodox theology to toll houses. The Orthodox are opposed to the dogmatic teaching on the Purgatory and especially to the popular idea of purgatorial suffering through physical fire, and of determined duration, but they are not opposed to the belief in certain process of purification of the saved after death itself and their opposition to the Catholic views is often a result of unfamiliarity with what the Catholic Church actually teaches on the Purgatory (on that, they often go by Protestant caricature of the Catholic belief).
Celibacy. A married man can be ordained an Orthodox priest, if it is his first marriage to an Orthodox woman. Such priest, however, may not become a bishop. If his wife dies, he may not remarry. Bishops can only be consecrated from celibate priests. The difference that exists on the level of parish priests is that of discipline not of theological substance. About nuns and monks, see next.
"Priests and nuns". What is that supposed to mean? The Orthodox most certainly have priests (men ordained to offer the Holy Eucharist, hear confessions, etc.); bishops (called in the East patriarchs) -- priests who also can consecrate other priests and other bishops, and have an apostolic succession to the same Apostolic College that we do; they also have monks and nuns.
See Wiki/Orthodox Church.
Thank you for your post. If you have questions or further comments, please respond.