I'm not sure about the weather in Texas but my gut feeling is that it will be too warm for the seedlings to thrive.
I don't use common names (they're too vague and often refer to more than one species) so I had to google them. "Coral Nymph" is a form of S.coccinea and although I couldn't find a definitive answer I suspect that the second one is a form of S.farinacea. S.farinacea is a Texan native, S.coccinea is a Mexican native so both should be perennial where you are.
If it were me I would sow earlier in spring but if you have enough seed you have nothing to lose by trying a few now.