Now that it's April, cold-hardy material should be breaking dormancy any day now, based on its storage. When the buds are beginning to swell is the best time to repot. Wiring can still be done as any damage will be repaired quickly when the tree grows. Your trees will need far more water when starting to grow, so keep an eye on the soil. Also, you can begin fertilizing as soon as the trees begin to grow. New growth will need direct sun; you may have to bring your trees outside during the day and protect them from frost at night.
Your tropicals will probably be at their weakest right now, after a long winter of low light, low humidity, and short days. Keep an eye out for insects; there are no natural enemies inside your home like there are outdoors. In a little over a month you'll be able to get them outdoors and growing again!
As always, if you have any questions we're happy to help!