Dynamic link is great, but can become extremely slow. I would stay away from it if you are doing any sort of complex effects. Export your effects from AE and import into Premiere. Quicktime Animation or an image sequence are good if you need an alpha channel, otherwise Pro Res should be fine.
Also, you are confusing bit rate and bit depth. Bit rate is how much data is included per second of video. Bit depth is how much color information is in each pixel.