I'm trying to make a Homebrew Monk subclass that has some minor spellcasting abilities. Unfortunately, even when enabling "Can Cast Spells", the spells section in the character sheet does not show up. Is there a way to get it to show up?

You have to add a class feature that is labeled "Spellcasting"

Wow awesome, not super intuitive in my opinion, but it works. Thank you very much!

Yeah, agreed. You're getting the actual dev forms we've used for official data, so they are not the most user friendly. We'll be doing another pass on all the HB forms in the future to make them much easier and intuitive.

Is there any way to modify the number of spell slots? The subclass I'm creating only uses cantrips and won't require any spell slots. If not, it's no big deal since I'm not giving access to any spells that would use those spell slots anyways

Currently the ability to modify the # of spell slots does not exist.

Is the ability to modify spell slots something that is planned for a future roll out? This is something I would like to see. 

As well a way to make progression in one class continue with multiclassing that provides the same spellcasting source. 

(example - using wizard spell list/progression and multiclassing wizard for continued wizard progression)