It looks quite nice! Do the rectangular planters have drainage holes?? If so, you might be ok, even with the "miracle grow" potting soil. If you mist the soil, it will only moisten the very top and the rest will stay bone dry. It would be better to moisten it thoroughly, and then let it dry between waterings. How much water? Keep adding a little more at a time, and then check the soil with your finger or by digging down with a trough, until the whole thing is moist.
Are you sure your original plants rotted from overwatering, or perhaps just from the shock and root loss of division?? It certainly seems that enough root/rhizome survived to put out a lot of new growth, judging from the photos!

It looks great to me, I remember your orginal post, don't see what you did wrong. They can break through the planters if they are not cement. I would not mist them, now that the offset are putting out new growth, you can water down at the soil line,they do have drainage? Then wait two week before watering again, do not use a mister. I think it may invite mold unless you have good air circulation. That species can take more water than the most and do better in a closed in envirenment. I see them in restaurents and banks all the time. Are they getting some light, they don't need much to grow, it looks good to me.

I posted in between there--but it disappeared..wierd.

Thanks so much for your responses.

The planters do have drainage holes. I thought I used the wrong soil mix and spread them out too much, put gravel in the bottom...Maybe I didn't mess up too bad?

The leaves that died started dying at the tip of the leaf. When I removed it, it was really mushy like it was full of water so I assumed that why it died. Plus, I could pull the leaf off and no roots were attached. Is this root rot from over-watering?

Should I fertilize?

If it was "root rot", not only the leaf, but also the rhizome would probably have rotted. Since the new growth is coming in good, it is probably fine. Maybe shock from change in growing conditions plus division? I think that Miracle Grow soil has some slow release fertilizer in it that will last a few months. Plus it is "new" soil and there is a lot of extra room, so there is probably still plenty of nutrients in tehre for them for a while. Maybe fertilize early next summer, when they begin actively growing again, IMHO.

Thanks everyone! Good to know. I have since watered them and hope they will do well.