You snapped some nice ones! The first one is A. tenuis. Still small, but very distinctive with the scale-like radials in a rosette.
Now it gets tougher! In the second I can't really see the radials and their mouths. It may be A. ceralis or, if the openings are nariform, A. nasuta. These are corymbose in growth, but, if the end form is staghorn, then other species come into the picture, such as A. microphthalma.
The third one looks a lot like A. millipora, but the axials are a bit long. It may be A. hyacinthus, which is a table of astounding grace when grown out. The problem with a foto is the proportions are lost. One can't really judge just how thick the branches are. Generally speaking A. millipora has branches twice as thick as A. hyacinthus. A. vermiculata should, also, be considered.
The last two are a bit too unclear to see the details. The last one may be A. elseyi.
Hope this helps,