When Prince Edward is made Duke of Edinburgh after his father dies, do you think his children will use the titles of royal ducal children?

It is not decided if he will be made the duke of edinburgh when his father dies, they may just not use that title anymore.

No. I'm not expecting their titles to change, except that James will use "Earl of Wessex" as a courtesy title. They won't use royal titles.

I suspect that although it was decided only informally that they would use the titles of an earl's children, non-royal titles for the children of younger sons of a monarch will be made an official usage -- perhaps by Charles.

Edward won't get the ducal title until after the Queen dies, too. The plan is for Charles to confer it on him once he becomes king.

Yes and no. Edward will be bestowed the dukedom and subsidiary titles. His son will take on the title next down that Edward bears, and will eventually inherit the peerage titles. Lady Louise will still be styled Lady, which is what daughters of a duke are called. Lord Severn and Lady Louise will not be royally titled, though. Edward and Sophie decided that their children would have more private lives styled as children of a peer. They were never going to take on official duties and Charles was interested in keeping the number of official working royals down and approved of his brother's and sister-in-law's decision. It is not likely the children would take on royal titles when their father becomes a duke because of the initial decision.

No. The title passes first to Prince Charles and will become extinct when he becomes king.

It will need to be recreated for Edward. His son would become Earl of Wessex, as an honorary title,

his daughter's title doesn't change as she doesn't have one (except honorary title of lady)

As Edward is already an Earl and Viscount, it may be that only

the Dukedom is conferred and possibly Baron Greenwich

depending on what the king decides. The Duke of Cambridge's subsidiary titles are

not the same as those of the previous holder, Prince George of Hanover.