The plan is to level through captain with science ships and then reexamine my options when I hit the admiral level.
Is this plan a good one and have I picked good abilities for my bridge officers? I was going for a mix of buffing and defensive abilities, and I wasn't sure if there was anything else I could do to improve my setup overall or if I was going about doing this the wrong way totally.
In my opinion, it is easiest to level in escorts, regardless of class.
^^ This. Also, my Fed engineer flies sci ships exclusively. The built in heals an engineer captain comes with allow you to give up some defense for offense in a sci ship. I run 4 offensive science BOFF powers with the Eng/Sci combination as opposed to only 2 in a sci/sci support ship. I also find the Eng/Sci combination to be the one I enjoy the most.