Is it okay how I cut the branches? Yes, as long as it doesn't start shedding profusely.

..... can keeping the cuttings in water for 24-48 hours be a problem for the schefflera and the ficus benjamin? No, but beyond that the water should be cool or well oxygenated. When you put cuttings in water, the water should be kept shallow, 2-3cm. The reason is, dissolved oxygen levels in the top 1-2cm of an unaerated water column are many times greater than at the bottom of a 15cm water column.

In the photo below you can see one of the pruned branches. Since this branch was only full at the end, the final effect is not pleasing to the eye. Will it improve over time? It should, as long as it approves of the cultural conditions under which it's grown.

Do the cut branches stop growing and send out lateral branches or do they simply fill with leaves? Once a leaf is separated from the plant, a new leaf will never grow in the same spatial position. A branch can grow from latent buds in the leaf axil, or, plants that produce adventitious buds can often form buds anywhere around the base of a branch. Single leaves only occur along extending branches. Removing the apical meristem from a branch terminates its ability to extend.

..... a group of leaves has accidentally fallen off: will they grow back? No. A branch could form there, but the leaves will not grow back.

The remaining encircling roots ^^^ were also removed before repotting the plant.

There is an interesting story behind this plant. I'm sort of the plant Dr at church, and the plant in the photos above was brought to me as something of a challenge. I was going to fix it and give it to one of the members, but a guy was searching GW/Houzz in desperation mode because his fiancé was out of country and he had killed her scheff via over-watering. He wanted to know how to revive it. After we discussed the idea there is only 1 degree of 'dead', it was decided that the plant he had seen in the post that documented the repot would be a suitable replacement for his GF's casualty and would (hopefully) ensure his continued viability. I sent it to Boston or NYC, I forget which. A week or so after she rec'd it, she sent the pic and a thank-you, and everyone lived happily ever after - at least I hope they did. I never heard anything more from them. I saved the image because it shows the prolific back-budding that occurred after the hard pruning.

Al

Yes, as long as it doesn't start shedding profusely.

What do you mean?

In any case, unlike the ficus benjamin, the schefflera does not seem to be in pain and 10 days have already passed since I pruned the roots. Does schefflera tolerate root pruning better than ficus trees?

A last question. This is one of the branches I pruned. As you can see in the photo below, I left a part that is completely before leaves. Can I hope that it will fill with leaves or is it impossible for this to happen and should I cut it near the other branch that goes upwards?