Cori:
I think your problems are related to moving the iris. Everytime I move an iris even under the best conditions, leaf tips die off or turn brown. You just have to give it some time to acclimate, and in a few weeks once new roots are formed, you should see some new growth in the fan center.
I usually clip the foliage when I do the move; it stresses the plant less, and seems to stimulate new growth.
There is nothing else you can do such as adding fertilizers to the soil at this point. Just make sure the plants are well watered for a bout 2 weeks to encourage the roots to grow.
Laetitia