I would not be alarmed. Transplant shock and the arrival of summer temperatures will make newly planted hydrangeas wilt and dry out some of the leaves. Lacecap blooms can also suffer and they do not last as long as mopheads. When your plant is established in your garden, its roots will be able to handle all this better. You can deadhead the blooms if you wish. Compared to mine, your shrubs look great! You should see hydrangeas here in Texas. When the temperature gets to 104 daily, just about every leaf looks wilted. Almost makes you want to say 'Oh wow! Poor thing'. Luckily, they tend to recover on their own by next morning. If they do not, I water them.

Yes, you should get leaves on the old growth. I am in Zone 4 and have 4 of theses. One of them is about 40 feet up the trunk of a large oak tree.

The root ball on the one in the middle, the brown one, may have dried out or almost dried out. Can't tell if this happened past the point of no return.I have one that almost bit the dust too several years ago. If you insert a finger into the soil near the crown and it appears to be dry, you may need to extract it and dump it in a pail of water to see if comes back. Leave it in water for about an hour until there are no more air bubbles. Alternatively, you can set a soaker hose to drip water slowly, very very very incredibly slowly as dried out root balls do not absorb water easily so hand watering does not help. Again, do not hand water it with a hose. Just let the hose drip... one drip every minute or every 30 seconds. Like a drip irrigation system. The plant may not leaf out again until Spring. I had one that did not leaf out when the temps went down in the summer but it sprung back in April instead. Or you can replace it. To make sure this does not happen again, use the finger method daily for 2-3 weeks. Insert a finger into the soil to a depth of 4" early in the morning. If the soil feels dry or almost dry, water the soil -about 1 gallon of water (1.5 gallons in the summer). Anytime that you water, make a note in a wall calendar. After 3 weeks, review the information on the wall calendar and determine how often you were watering: every 3 days? every 4 days? etc. Then set the sprinkler to water 1 g.5 gallon on the same frequency (every 2/3/etc days). If the temperatures change more than 10-15 degrees and stay there. use the finger method again to see if you need to tweak things. Maintain 3-4" of organic mulch to conserve soil moisture and make the waterings last longer.

Here are some possible answers to the problems you are having. Some plants are sensitive to insect sprays, so I usually test on one leaf before using on the whole plant. I don't know if this applies to hydrangeas. Potting soil that plants come in often isn't the best long term medium, and those pots look way too small for the size of plant in a normal, non-nursery situation. Your type of hydrangea needs even moisture, so I'd repot in a larger container with a potting mix that is coarse enough to drain well, but with enough organic matter to remain evenly moist. The Container Gardening Forum may be able to help with this. For right now until you've repotted, you don't want the soil soggy or dry. I would give your plants, which look like a cultivar of Hydrangea macrophylla/big leaf hydrangea, sun in the morning before you go to work, and perhaps after supper or in the very late afternoon, but leave them indoors during the day since they aren't plants that like full sun, but also won't bloom well if kept indoors all the time. Ulitmately, these will be extremely high maintenance plants in your setting. I really try to buy plants that will do well in their setting without extraordinary effort from me. So for a sunny balcony, I would use sun-loving plants such as mandevilla vine, Salvias, Pelargoniums/geraniums, etc. or get a sun-loving Hydrangea such as H. paniculata Bobo.