Depends on form factor etc. I presume you want wall mounted but do you need them flat, lifestye styled etc.
If you are taking tiny sats they will have limitations. But good ones should be better balanced than these. Try the kef sats I guess. or revel if they carry what you are looking for.
Better yet, sell the sopra set and get a matching set of revels.
you really do not need to worry about using the same brand for the surround. Especially for atmos or surrounds for films. And unless you have 5 of exactly the same speakers, not the same brand or model line but the exact same model of speaker, or extremely close too it (such as KEF Q350 fronts and center and KEF Q150 surrounds) my experience is that surround music will never be even somewhat timbre matched anyway.