Welcome to the forum, foxngn.
Your plants are growing happily at your place, provide them with more sun light if you can. All your sundews species will turn more reddish if they get more sun, especially the D. intermedia 'cuba'.
As for D. burmanii, the plant normally shrink after flowering. I normally cut away the flower stalk to "keep" that healthy look.
But if you want seeds, then you would have to risk the plant to death by letting the plant to flower then get seeds to start the 2nd generation. It doesn't mean that the plant will surely die, it could survive if the plant is strong enough before it flower.
D. burmanii eventually become weed, they invaded almost every nearby pot in my garden!
