It is possible to transfer your characters between Bard's Tale 1 and 2!
To do so, you need to open the Disk Management screen, which on desktop can be accessed using the F4 key, and on mobile, using the disc button on the virtual keyboard screen. You will see Slot 5 Drive 2, which is where the character disk goes. You can drag the character disk from Bard's Tale 1 into that slot, and that will allow you to use your Bard's Tale 1 characters in Bard's Tale 2.
Note: The Bard's Tale 3 does not allow any character importing. The version of Bard's Tale 3 we used is from the Apple II, not the Apple IIGS like the other two games. As such, the character files are not compatible between them.