Did you check the soil in the pots yet to see how wet or dry it is? Were they in partial shade? It may be a fungal or bacterial problem.

The grapefruit was in full sun. The avocado was against my house so it was in partial shade during the day. But look at this picture. This is 4 hours later and the avocado perked right up! I think it NEEDED water, and the rain helped it. But I could be wrong. Maybe taking it OUT of the rain helped. The soil in both feels damp, but it did rain here all day so..... I think I'm going to go try running some water in the grapefruit soil. Maybe that big cananopy is preventing it from getting a good dousing that history tells me, it likes a lot.

The grapefruit leaves are curling from the sides, not the ends. See below:

In the past when my grapefruit has dropped leaves, it was water DEFICIENT. This was difficult to figure out because when I would try watering it, more leaves would fall off - making me think it may have been TOO MUCH water and by watering it I made it worse! But I've learned that there is a delayed reaction with this tree. It DID need water, but by giving it the water it needs, it wanted to drop the half-dead leaves so it could grow new ones. Because immediately after the leaves fell off new leaves started growing. In fact one year it bloomed and I actually got 2 grapefruits. (And I grew this in Syracuse from a seed I planted from a store-bought fruit!)

Your grapefruit tree is large enough that the leaves would shed most of the rain past the pot. Your canopy is 4 times the surface area of the pot so even a heavy rainstorm would only get 1/4 the water as an if it were in ground. Probably to dry.

Steve

The drooping leaves indicate that there is probably an issue with the roots. The leaves look healthy otherwise, but the roots just cannot supply them with enough water. You will likely need to increase the size of the container giving the roots more space. Either that or prune the rest of the tree to a smaller size, but even then the roots probably need to be taken out and the edges trimmed to avoid it becoming rootbound.

A rule of thumb, the roots need a similar amount of space to the size of the plant's canopy.

The palm looks sunburned from not being acclimatized to full sun for long enough in the spring. Some thrive in full sun if acclimatized, but others need shady garden spots for beauty and health.

The other issues I think are from the drastic seasonal changes. I would be curious to know the surface temperature of the totes in July with full sun when the soil is near dry. I suspect the roots may have overheated.

How long has the trees been growing in the same container without being repotted? Have you ever slipped the containers from the tree to actually inspect the condition of the root system? I believe your tree's problems are in the root ball system.