Mt experience is that most of the hotels in Dolomites 3-star and up have some kind of spa facilities. It is something they need to offer to stay competitive with their counterparts. They can range from minimal to ultra luxurious. The hotels you mentioned are in the Pustertal area on the north end of the Dolomites, not near the really spectacular Dolomites. That would be, IMO, Ortisei, Santa Chistina, Selva di Gardena, Corvara, Canasei.
Ortisei is a popular choice since cable cars take you up to the Seiser Alm or Alpe di Siusi. The Hotel Adler is top of the line, but I don't think you'll find anything there for anything close 100 EUR/night. 300 EUR/night maybe in shoulder season.
Prices will vary considerably depending on the season. It is ski season now and all hotels will be charging their highest prices. July and August will also be super prime time pricing.