I'd recommend Yamaha for its combination of sound quality and reliability. Many people here have had good success and gotten great prices from Accessories4less.com. They deal in new units that have been factory refurbished by the manufacturer, so basically they're like new with full warranty. If they don't need all the latest bells n whistles, they can save a bundle by buying a model that's a generation or two old. Here's a model from Yamaha's upscale Aventage line that's not the newest model but still offers Airplay, Bluetooth, and streaming from various services including Spotify. At 90Wpc it should drive the Spicas just fine, within reason. Retailed for $750 new but you can get it now for $300.
https://www.accessories4less.com/make-a-store/item/yamrxa760bl/yamaha-rx-a760-7.2-ch-x-90-watts-a/v-...If they want more power and can spend a little more, this $480 Marantz (retailed for $1000) has a similar feature set but puts out 100Wpc with a beefier power supply that probably does better with sub 4-Ohm loads if they're really gonna crank it.
https://www.accessories4less.com/make-a-store/item/marsr5012/marantz-sr5012-7.2-ch-x-100-watts-a/v-r...As they're not audiophiles I'm sure they'll be thrilled with either, so their decision may come down to price and looks. One other thing that might factor into the final decision -- Yamaha has been one of the most reliable AVRs on the market to the point where you rarely, if ever, hear of any problems. Marantz isn't bad on that score but not as good as Yamaha, and they have had some issues in the past. I'd definitely avoid NAD, Onkyo, and Harmon Kardon due to very spotty reliability in the past. Hopefully somewhere in there they can find a balance. Anyway, hope this helps and best of luck in your search.