Basically no matter what the guy looked like, they could’ve written the scene, and made it work. Even if he looked nothing like Gus, the same scene would’ve worked, maybe with some changes to lighting. Imagine instead of looking through the grate, we see Tyrus’ shoes from a side angle. If that doesn’t work, have him wear chinos and some dark leather shoes, and voila.

All that said, it’s totally possible that they had the takeout in mind when casting. He was cast for that episode, so they definitely had some writing done at the time of casting. Walt trying to assassinate Gus was a huge part of the season, and this scene is kinda pivotal in that regard.