Less a "MUST be" than a "should be", and arguably actually canon:
According to quite a number of sources (probably all deriving from the Wikipedia article on the company), one episode of Angel includes a claim that Yoyodyne Propulsion Systems is a client of Wolfram and Hart.
Yoyodyne, for those not familiar with the name, is the company run by Red Lectroids in The Adventures of Buckaroo Banzai Across the 8th Dimension.
This means that it is arguably Buffy/Angel canon that the events of Buckaroo Banzai occur in the background, where nobody's paying attention to them - and, by corollary to that, that Buckaroo Banzai himself exists in the Buffyverse.
This simply demands to be taken advantage of in a fic, but I've never seen one that even tried.
(Edit: Bob, this also means that you have the opportunity to actually combine two Steps if you want to... or use one to revisit the world of the other, with Doug not realizing they're the same world, at least not at first.)
According to quite a number of sources (probably all deriving from the Wikipedia article on the company), one episode of Angel includes a claim that Yoyodyne Propulsion Systems is a client of Wolfram and Hart.
Yoyodyne, for those not familiar with the name, is the company run by Red Lectroids in The Adventures of Buckaroo Banzai Across the 8th Dimension.
This means that it is arguably Buffy/Angel canon that the events of Buckaroo Banzai occur in the background, where nobody's paying attention to them - and, by corollary to that, that Buckaroo Banzai himself exists in the Buffyverse.
This simply demands to be taken advantage of in a fic, but I've never seen one that even tried.
(Edit: Bob, this also means that you have the opportunity to actually combine two Steps if you want to... or use one to revisit the world of the other, with Doug not realizing they're the same world, at least not at first.)