You might want to skip the canister filter and just add more Live Rock. Canister filters can really cause nitrate issues, especially if you aren't using RODI
Word of caution on the AI Vegas: They are great lights (I use AI Sols myself) but they are extremely powerful. Start them off at a very low level and adjust accordingly. The PAR readings for these fixtures are similar to the Sols, and I run mine at 35% white, 45% blue over a 57 gallon tank.
Not having a sump is not a huge issue but there are obvious advantages such as adding additional water volume to the system, and hiding equipment. However, with additional live rock in the DT and a skimmer, you can have a successful tank without one.