If you check the Zircon repo, you will see that they are backing in a linux virtualization layer in the kernel, so i imagine they will use that to bootstrap android linux apps in Fuchsia as a staging process, until android apps are completely native in a second phase.
Chrome OS already runs Android, so it would be a matter of stitching the Chrome os shell into Fuchsia to have both running in Fuchsia. First with virtualization of Linux, and later without it.
There is some signal[1] that maybe Fuchsia as an OS will support Android apps out of the box. As I'm sure we both know though, ANYTHING can happen between now and the ship date.
it's a brand new operating system that google is experimenting with.