Hazel - this is one time you don't have to feel guilty for being lazy.
Lupine only bloom once in a season and then normally will die right back. Let the seeds fall where they may. Or, let them get ripe, then deadhead and sprinkle seeds where you want them. They may or may not sprout next year.
As for your seedlings - fall is the best time. You can take a chance and put them in the ground now but they may not survive a hot summer. You said you have them in peat pots? Plunk the whole darn thing in the ground. That way there is no disturbance of roots, which lupine hates, and a better chance of survival.