The Premier League-proven Wissa was supposed to help ease the burden, but he hardly had the ideal preparation.
The striker did not have a proper pre-season, after pushing to leave Brentford, and suffered a knee injury on international duty with DR Congo only days after joining Newcastle.
He nonetheless scored two goals in his first two starts, but has found the net only once since.
Winger Anthony Gordon was even handed an extended run through the middle ahead of Wissa before Osula got his chance.
Newcastle’s recruitment record has historically been strong under Howe, but they have not seen enough of a return from a desperate £55m move.
The same can be said for an overall £100m-plus net spend last summer.
It was a turbulent period in which Newcastle missed out on a host of first-choice targets, operated without a sporting director and chief executive, and made the overwhelming majority of their signings when the season was up and running.
Howe was heavily involved in this recruitment drive, but it was rather telling that only one of Newcastle’s five outfield additions – Malick Thiaw – started against Palace.
Jacob Ramsey and Anthony Elanga will be pushing for recalls for the visit of Bournemouth on Saturday, having been named on the bench alongside Woltemade and Wissa at Selhurst Park.
But Howe was not exactly proactive in turning to the quartet – even after Palace sounded a warning when Jefferson Lerma headed against the crossbar in the second half.
It was opposite number Oliver Glasner who ultimately seized the initiative with his substitutions.