Often in hot weather it's best to cut away most of the fronds on the fern. Damage to the root system slows uptake of water, but the fronds are constantly giving off water at a fast rate. The plant in between dehydrates.

You could leave them as they are a hope for the best (while still giving them a lot of water and wetting the fronds). Or you could cut away some of the fronds and slow down the loss of water from the plant. Depends a lot on how much damage was already done, and how hot the weather stays.

If your neighbour offers some more then I'd trim the fronds before planting. You could also put them in a pot and keep them in a humid place until they establish themselves. Then you can plant them out when the weather is suitable and the plants are healthy again. But I wouldn't worry too much. We're all on a steep learning curve with plants, just some of us are a bit further along on that curve, but still learning.

Thank you for both the advice and support!

You have made a good effort. I do like to transplant a bit earlier in the spring but sometime you need to take the chance when offered.
Having transplanted many and different varieties, i find the first year is a bit sloppy looking but they have a good chance of coming back strong next year...

soaker hose is a good thing to give them. I have mine hooked up to a manual timer,
(a reasonable 12 bucks at my garden center). If the week is a busy one i can just set it for 30 min on the way in the door and i never forget to turn it off.

I'd never thought to cut them back a bit. I may try that next weekend.

Ostrich ferns are a blessing and a curse...they're a strongly growing fern...and thus an aggressively spreading fern (by being strongly growing).