We sell both the Dali and Kef lines as well as many others ATC, PSB, Paradigm, Legacy, and a few others.
It sounds like you have to have a really pretty pair of speakers as well as good sounding ones.
A few things to consider in helping you narrow down your choices:
1: Room Size
2: Efficiency of the loudspeakers
3: Matching center channel
4: Does the company make less expensive lower line products that can work for center channels or backs.
5: Sound quality does the speakers sound musical and will do both jobs well ie Music and Theater
Personally we recommend on moving to a floor stander whenever possible as the added bass will increase the sound quality greatly also as the bass goes lower, it is easier to get that speaker to blend with a sub.
Out of the lines you mentioned KEF is really the best product to do both Theater duties and music duties. Here is why:
The Kef Reference One is the only speaker you have mentioned which use a point source and qusi horn loading; This is advantagous for a number or reasons:
1: Broad off access dispersion which means where ever you sit you can hear al the information
2: The point source design makes for a very coherent sound
3: The speakers play very loud a pair of Ref 1 are rated to produce 111 db output
4: They are a true three way design with low bass down to 45hz which will make them easier to blend with a sub and considering you have a Kef sub easy.
You can also use an R series Center channel to save money until you can move to a Referene one, which is what we did in our theater which uses Reference 3.
The Dali Epicons are wonderful speakers but are not as well suited for the Home Theater thing, they don't play as loud and the lower priced Rubicon center is not as good a match as the Rubicon center uses the hybrid tweeter array. The Dalis are fantastic for music, if you want to blow your budget and can fit a pair of floorstanders we have a demo pair of Epicon 8 selling cheap to make room for some new additions.
Wilson Benesch is a two channel company I don't even think they make center channels. Dynaudio makes good speakers but they are not as ideally suited for home theater as the KEF's are.
Focal Sopra 1 are great monitors the only issue is their Beryilium tweeter may show up defficiencie of your gear unless you are willing to invest considerably in the best home theater processor and amp you may find them a bit too detailed for regular TV and Movie watching.
To show you we practice what we preach here is one of our theater which uses KEF loudspeakers:
Here is the movie theater we built for Rev Run of Rev Runs Rennovation
and featured on TV:https://www.flickr.com/photos/58319891@N08/albums/72157650233548529
Here are the construction shots note KEF THX in walls with JL Audio Subs:https://www.flickr.com/photos/58319891@N08/albums/72157650239108910
If you watch our store video you will see our KEF Reference Theater:https://www.youtube.com/watch?v=1NPIn3pEmI4
If we can be of assistance to you please feel free to contact us:
Audio Doctor NJ