Easter lilly can be planted out now, take into account that it has allready bloomed and will die back. Make sure you let it die back on its own as the greenery will feed the bulb. The amerillis I have not ever had luck putting it out so I could not tell you, allthough if you plan on bringing it back in I would plant the whole pot in the ground so it will be easier to bring back in.

Happy Gardening
Mark

Amaryllis will bloom and then for a fair length of time will be a foliage plant. During this period you hope to have it in good sunny location where it will store the energy needed to bloom again. If your plant is in this stage, putting it outside after danger of frost makes sense, but then it must come in before fall frost. If it is already beginning to die back, keep it in a sunny window and let it die back. After die back, store in a cool dark place and wait for the next cycle.

Do not cut back the easter lily. It needs to store energy.

I put my Amaryllis out in June, in their pots to enjoy the summer. They like warm temperatures and it is much too cold at night (and during days even) for it to be outside now. Keep it inside near a sunny window if possible. Water it regularly. Don't cut the foliage (except the spent flower stalk). If you cut the leaves off it is sure to not bloom next year. Then when it is outside for the summer, give it liquid fertilizer. I keep it in the pots - I did an experiment one year planting directly in the ground but found it easier and better result to keep in pots. It can take a fair amount of drying out when outside (so you need not water it as much as other container plants). If the amaryllis bulbs were from discount places my experience they don't rebloom as reliably. Then in fall in late Sept I take the pots in the garage and hold back watering. Eventually the leaves die. They are now dormant. Then I move them to my basement until Jan-March time frame, not watering at all. I then bring them upstairs and water again. They will start to grow and rebloom at this time. Then repeat the cycle. My rule if a bulb doesn't bloom one year I don't waste time with it and just compost it.