I think anything bareroot benefits from striking roots in soil where you can regulate the water intake and temperature. I would start them both inside in order to bring them back to life. The elephant ear likes warm soil temperatures to start rooting. Have fun with those.

For the Trilliums, go ahead and pot them and apply moisture, the sooner, the better. They will begin to emerge when their internal clock and soil temperature (normally about 55°F) reqirements are met. Sometimes, they do not set blooms the first year, when they have been out of the soil for an extended period, but there should be enough stored calories in the tuber to produce foliage.
I have several hundred growing in pots and I just keep on collecting and planting seed! I wouldn't mind if my entire garden were covered with them.
Enjoy!
RB