Yes Orlando has the rights to claim him.
This isn’t baseball. If you don’t sign a rookie tender, you don’t get to go to the draft later. I’ve stated before in questions/suggestions that the only players eligible for the rookie draft are the ones that were eligible for that years real life draft. And the eligible players list shows the 60 drafted players and stats “any undrafted players eligible to be drafted.”. Okeke is not an undrafted player eligible for the 2020 real life draft.