The new growth from the bottom can be selected and make new trunks that will grow larger over the coming years. Stop cutting them out until you are sure the old ones are alive or dead. Have you tried a scratch test to see if the cambium layer on the "old" trunks is still alive? The cambium is just under the bark - if it is brown, the branch is dead. Check a few of the branches on the old trunks to see. If there is green, then keep waiting. My CMs are still in slow mode and have done little as yet - I had 2 which had leafed out and got frosted, but all of them are mostly sitting, except for bottom shoots. You may get sprouts from the roots for the life of the tree - some CMs do and some don't. As I said, if the "old" trunks are dead, then letting as many new stems grow up as you want (I suggest 3-5, but it's up to you), will replace them. Just cut out the dead ones, carefully, so as not to damage their replacements, then let the new ones grow over the summer. You may or may not get flowers this year. And if there is another major cold spell, either before they go dormant, or in late spring, you may have it all to do over again. Just be thankful the CMs have strong root systemsd and can come back. Resist the urge to fertilize them for another few weeks, until you know what's happening to them. CMs don't need much fertilizer anyway.

Crystals..I don't know of anyone who irrigates their crape myrtles beyond the first couple years after planting. And, you may be putting your fertilizer too close to the tree trunks. Here it is 3rd week of Aug and most of the crapes in yards and in pro intallations/street medians are blooming late and fully. We have, in most of Meck. Cty, had more than enough and regular rain. I'd stop babying these decorative small trees and focus on the fall/winter trimming and removal of the drip lines. Move the drip lines at least 6' from the trunk and root ball area or take it away altogether.

You're further south than me though, so I'd expect yours to leaf out earlier. Here we don't see leaves on crape myrtles for another couple weeks, and none of the others in the aria are showing any signs of it yet. I guess it could just be a combination of unseasonably warm weather and location. It's not exactly a sheltered spot where this seedling overwintered, but it isn't as exposed as a tree standing in the open.

bdeimel, if those were my trees, I'd most likely not cut anything just yet. I'd let them sprout growth wherever they were able and let that become my guide. Then later in the season when it's clear what's alive and what's dead, I'd begin removing the dead wood. Once you're down to just living wood, I'd then begin to prune for shape (much like you do any regular tree). There is an exception to cutting out the dead wood: If that wood is helping the new growth to "stand" upright instead of flopping over, then I'd leave the dead wood in place until the new growth can hold itself up without help. So, in effect, the dead branches would serve as stakes, holding up the new growth. If the tree's shape would be permanently deformed in the end, you may want to cut the entire tree back to the ground and start it over. It's a little late in the year to do that now so I'd probably wait until next year. Plus, by then, you should have a better idea of what the tree will look like with the new growth and then can make a more informed decision on whether to keep it that way or cut it down and restart it.