The following revision refers to this bug:
  https://chrome-internal.googlesource.com/infradata/config/+/b1ce71ec0b57f3503b441e581855877169f6b389

commit b1ce71ec0b57f3503b441e581855877169f6b389
Author: John Budorick <jbudorick@google.com>
Date: Tue Dec 18 23:41:36 2018

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/tools/build/+/a98e66b1a581a3e9d4c2d0b569de517d81e52489

commit a98e66b1a581a3e9d4c2d0b569de517d81e52489
Author: John Budorick <jbudorick@chromium.org>
Date: Wed Dec 19 01:08:02 2018

Recipe configuration for fuchsia-fyi-{arm64,x64}-rel.

Bug:  909006 
Change-Id: I7eb35bde8840ec68b577797e68b0df5ec0007e90
Reviewed-on: https://chromium-review.googlesource.com/c/1383371
Reviewed-by: Stephen Martinis <martiniss@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>

[modify] https://crrev.com/a98e66b1a581a3e9d4c2d0b569de517d81e52489/scripts/slave/recipe_modules/chromium_tests/trybots.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/316f06337caa9a7ad2f117ddc79e68c600bb91c7

commit 316f06337caa9a7ad2f117ddc79e68c600bb91c7
Author: John Budorick <jbudorick@chromium.org>
Date: Wed Dec 19 03:29:05 2018

Add luci and compile configurations for fuchsia-fyi-{arm64,x64}-rel trybots.

Bug:  909006 
Change-Id: If556db805a905f90f243747db8f2b0915d5bc83c
Reviewed-on: https://chromium-review.googlesource.com/c/1383328
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617719}
[modify] https://crrev.com/316f06337caa9a7ad2f117ddc79e68c600bb91c7/infra/config/global/cr-buildbucket.cfg
[modify] https://crrev.com/316f06337caa9a7ad2f117ddc79e68c600bb91c7/infra/config/global/luci-milo.cfg
[modify] https://crrev.com/316f06337caa9a7ad2f117ddc79e68c600bb91c7/tools/mb/mb_config.pyl

Bots are all set up:

https://ci.chromium.org/p/chromium/builders/luci.chromium.try/fuchsia-fyi-arm64-rel
https://ci.chromium.org/p/chromium/builders/luci.chromium.try/fuchsia-fyi-x64-dbg
https://ci.chromium.org/p/chromium/builders/luci.chromium.try/fuchsia-fyi-x64-rel

Re #4: Thanks - trying an FYI Debug run on an existing CL, looks like things are working as expected. :D