Aha! Gotcha. I ended up swapping them around since I don't need italic support in my text (btw, love the bold italic auto-font thing. really nifty!) so I did this:
local originalSystemFont = playdate.graphics.getSystemFont()
gfx.setFont( originalSystemFont, playdate.graphics.font.kVariantItalic )
gfx.setFont( "myFont" )
So now, i can use all of them, within my custom font by just wrapping them with the underscore.... "This is the b button icon: Ⓑ"