I decided to jump into modular with the new Bastl Citadel modules. I had previously owned two of their SP2's and loved them (quite buggy though). I have Moog semi-modulars but have never built a full modular rack so I'm worried about missing something obvious. 

    Do I need VCA? Sequencer? Any cheap 1u utilities? (Figured I can sequence w/ the DFAM/Subharmonicon if needed). Do I have to worry about power consumption? (503 mA +12V | 238 mA -12V | 0 mA 5V) I really have no clue what I'm going to be able to do with this rack besides glitchy drums - I know it would be cool to patch the DFAM in. I'm sure it'll be a learning curve. 


Yeah, the learning curve can be a bit steep in the beginning. That said, this is a really weird rack. ;)
Power consumption shouldn't be a problem, the Intellijel 4U Palette provides up to 1.2 A per rail.
What you need depends entirely on what you want. You don't need a VCA if there's no need for amplitude modulation. But you might want something like this: https://intellijel.com/shop/eurorack/1u/stereo-line-out-1u/ to connect to your 6.3 output jack and reach the outside world. Be careful - modular level is not line level! Modular level is quite a bit hotter!