I think it's very unlikely that the child will carry the title "of Sweden" after their brothers had it revoked from them in 2019. The king's sisters who lost it by making unequal marriages likewise have not had it restored to them.
From my reading, the law on royal coats of arms is just as "clear" as the law on orders (I quoted both in my post above) in denying them to non-members of the royal house. Neither law forms part of the constitution, as far as I can tell.
It is a misunderstanding that they had their titles removed. The only thing removed was their ”H.R.H-prefix” and thus their status as a Member of the Swedish Royal House. Their titles are
Alexander, Prince of Sweden, Duke of Södermanland.
Gabriel, Prince of Sweden, Duke of Dalarna.
In Sweden there is a difference between being a member of the Royal House (everyone carrying the prefix of H.M and H.R.H) and members of the Royal Family (wich also includes everyone without a prefix).
Regarding Coat of arms, every Knight (or if female Member) of the Royal Order of the Seraphim have their own personal coat of arms.
As Princess Christina, Desirée and Margaretha was made members of the Order of the Seraphim in 1952, they still have their own Seraphim coat of arms, hanging in the ”Halls of the Royal Orders” at the Royal Palace, together with every other living Knight/Member. Just like Gabriel, Alexander, Leonor, Nicholas and Adrienne was born as ”H.R.H” and recived the Seraphim before they had their ”H.R.H-prefix” and status removed... This child will have nothing removed as he or she will never be an ”H.R.H”, and thus not be eligible for the Royal Orders until the change in the constitution has taken place.
The only swedish royals who has had the ”Order of the Seraphim” taken away from them were 2 of the uncles of the current King, Prince Sigvard and Prince Carl Johan, when they had morganatic marriages... They were restored to the Order of the Polar Star by their father King Gustaf VI Adolf after his accession but not to the Seraphim.