I suspect this is the problem causing the delay. They have a chance of some decent looking options available in the summer, but aren't sure about Unsy until the end of the season. The Allardyce thing could be media invention, played up to by him, but after hearing nothing from us now he's changed his tune. The 'someone until the end of the season' trope in the media is educated guesswork (possibly confirmed to some degree by some source) but the Allardyce and Dyche links are just the media playing their game. Silva and maybe some of the big names are possibly true, although again mostly guesswork I would think. The media must be loving our lack of action, means they can spin something new every day and we'll keep on clicking.
Yeah I don't think Prentice's comments were guesswork. It wasn't written for clicks, it was said on a podcast with a clear indication that he had the information from a source.
The reason I believe it is that he isn't a sensationalist or click bait merchant. If he doesn't know something or hasn't heard anything he tends to just say 'I don't know' rather than just blag it.