I found measurements of the Oberon 5 and the Elac FS 5.2 (smaller model than the FS 6.2) from germany magazine Stereoplay:
The frequency response of the Oberon 5 has a V shape, meaning that the presence region is recessed while upper bass and brilliance region are elevated. This kind of tuning is popular with many manufacturers, because it sounds full and sparkly without beeing screechy. Some call it „showroom sound“ because it tends to impress customers in dealers showrooms. The big question is how pleasant the sound will be when the novelity factor wears off…
I wouldn´t read too much into the measurements of the Elac FS 5.2 since you are interested in the bigger FS 6.2 model and we don´t know how representative the smaller model is for the bigger one. But I think it´s pretty safe to assume that the Elacs will have a more pronounced 2-6khz region while the Dalis will be more pronounced above 10khz.
That being said I think the Oberons look much nicer than the Elacs.
Considering the amp I would probably go with Yamaha AS 301 or 501. Good value and Toslink/Coax inputs, but I wouldn´t expect them to sound any different than any other decent amp in it´s class.
Where are you from? Media Markt/Saturn from Germany are currently selling the Elac Debut Reference DFR52 for 638€/pair (but they only deliver within Germany). They employ 5.25 inch woofers instead of 6.5 inch ones, but looks and value seems pretty good and since you plan on adding a subwoofer later…