You had incorrect information on both counts.

1) You will receive a complimentary hotel + visa + transfers + meals voucher regardless of whether you are booked on points via another airline. In Cloud Nine, that voucher will almost certainly be for the Skylight Hotel. I have literally done this multiple dozens of times on award tickets over the years without a single issue, most recently just 3 weeks ago.

2) The "In-Terminal" Skylight Hotel opened in September 2022. It does not require a visa, but obviously services are much more limited and will (usually) not be eligible for the accomodation voucher. It is easily located in the terminal - just follow the new GREEN signage that they have put up everywhere on the departure concourse.

With the relatively long (12 hrs) duration of layover you have, I would not hesitate to use the ET provided voucher for the main Skylight Hotel. The airside hotel is best suited IMHO for 4-8 hour shorter stops which are too long for the lounge and too short to go into town.