I can't help you out with the other two, but the D. adelae that I have
(grown from seed) is blooming away 20cm back from and just to the side of a
west facing window. It gets a few hours of filtered sun per day with bright
light through the rest of the day. It is in a 12cm pot and watered every
day in the spring and summer and kept just moist during the winter. The
plant just fills the pot with its leaves touching the edges. No sign of
seed, though. I suspect that it could take a tad more sun and get more
colour, but "why fix it if it ain't broke?"
Regards,
Rand Nicholson