Keep the colors light and bright and glass enclosures and it will appear bigger.  

A basement may be used for habitable rooms or a dwelling unit, regardless of the depth of the floor below grade, if the floors and walls are impervious to leakage of underground and surface water and are protected from dampness, and if the required minimum 13-172-130, or by other approved means. 13-172-070 Natural light.

What guest policies are you comfortable in light of COVID? 

We got quotes form several builders - $195-225k before fixtures and furnishings (so assume $220-250k all in) - for a 430 sqft ADU above a 430 sqft garage

So is new cabinet hardware and lighting.

I had a light bulb moment the other day when I was estimating what it would take to leave a 9-5.

Consider a motion sensor light on the side of the house.

I decided going forward to allocate a portion of my budget strictly for capex repairs that would typically be covered by a warranty co.Hope this shines some light for you.

For instance, the guy that lived in the US and liked surfing and, at some point, having financial stability (i.e. property already paid off in the US, or money saved, or able to telework), had that light bulb moment to relocate to Bali when it was cheap... really made it.

The basement has brink walls like the picture and track lighting already installed.