Responding to this may be a little difficult, due to the diversity of practice among the OO. However, I'll try to point you to a few previous threads that deal with some of these issues. Looking through the OO section a bit may help you uncover some other threads dealing with questions you have.
With regard to vestments, Armenian vestments are similar to EO ones, with a few differences. For example, an Armenian priest or bishop has a high collar around the back of his neck, which EO priests don't wear. Also, Armenian priests wear a crown during the first part of the liturgy, like the EO bishops wear. Armenian bishops wear a mitre, similar to the one worn by Catholic bishops. That is something we borrowed during the Crusades. In this video of an Armenian priest being ordained, you can see both the vestments of a bishop and priest. In the video, you also see a clergyman with a black pointed hood. That may be another bishop, or a celebate priest. The black hood is worn by celebate clergy:http://youtube.com/watch?v=kwVlMxeG7zY
Coptic priests during the liturgy wear a much more plain vestment, I think made of white cotton. I think that is the more ancient practice. In the video which is the subject of the following thread, you can see a Coptic priest with his white vestments and mitre:http://www.orthodoxchristianity.net/forum/index.php/topic,11887.0.html
Here is a thread about a video describing Ethiopian practices and vestments:http://www.orthodoxchristianity.net/forum/index.php/topic,13908.0.html
Here is a youtube video showing a Syriac bishop:http://www.youtube.com/watch?v=FnXcKYNOsAw&NR=1
There have been various threads about Holy Communion. The Armenians have the most unique practice. We use unleavened bread to show that Christ was pure (yeast represents sin.) We also give Communion by intinction, with the priest putting the Communion into the mouth of the faithful, using his fingers. We don't use a communion spoon.
Other OO's use a communion spoon and leavened bread. In the Coptic and Ethiopian Churches, the Body of Christ is given first and then the Blood of Christ is given.
Here is one thread I could find:http://www.orthodoxchristianity.net/forum/index.php/topic,13147.0.html