I doubt this. The Harkles may be happy to go behind backs and do their own thing, but Eugenie and Jack don't rock the boat. The cousins have stayed in touch, and maybe they discussed renting Toad Hall, but I don't think Harry could just rent out Frogmore without going through channels. The original scenario makes more sense, that the Harkles had the rest of their things sent to them and the Brookbanks are now living there.

https://www.dailymail.co.uk/news/article-8973931/Meghan-Harry-struck-deal-hand-Frogmore-without-knowledge-royals.html

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