There's a chance the reservation will be fine, I don't want to mislead you otherwise, but there is definitely some level of risk renting during an owner priority period through a website like VRBO. If I had to quantify it though, I'd probably say you're more likely than not to be ok. Again, it's just all about your risk tolerance.
I wouldn't feel too bad for the owner though. First, I don't know anyone who "just has extra points to get rid of this year" who is renting on Vrbo. This is probably some level of commercial renter who is renting for a profit (which is exactly what Wyndham is targeting). Second, through a quirk of Wyndham's calendar Easter falls during value season next year. Not sure what he was charging you for the rental in a 3 bedroom for a week, but depending on what points he was using he was probably only paying about $1,000 in maintenance fees for a week in a 3 bedroom, and if he had some real low maintenance contracts, and/or was using VIP auto-upgrades, he could have been paying far less, maybe as low as $500.