Correct. You can record with the Zio as the DI. It has a balanced XLR output and you can adjust the output level up to line level with the volume control as needed, or pad it down if needed. If you are going directly into a microphone input you may want to engage a pad on the mic pre as well, depending on the preamp (some have a high minimum gain). For a line level input you should be fine.
To answer the transformer question, the Bass Zio does not use a transformer for the output. It's electrically-balanced using high quality Burr Brown audio op amps that are designed with use as a DI output as one of the applications. However if you do want some transformer-like flavor, the Grit circuit is based on transformer non-linear behavior.
