JMLab Electra 906 / CC900 vs. new Focal Be's

I have a home theatre comprised of 4 x Focal/JMlab Electra 906's and an Electra CC900,
and I am looking to upgrade to Focal's latest offerings.

I am thinking about adding an SW 1008 Be subwoofer, then progressively replacing
my old 900-series Electra's with a CC 1008 Be center, some 1028 or 1038 Be's as
front speakers, and using my existing 4 x Electra 906's for sides and rears.

Has anyone any listening experience in comparing the old 906's (non-Be)
to the new Be series?

While there's no doubt in mind my mind that the new Be's will be vastly better,
my concern is that if I use the 906's as surrounds, they will sound too tonally different
from the new front/center speakers, and I will lose the uniformity that I currently have
(forcing me to upgrade to new Be surround speakers, which will be a pretty
expensive exercise!)

Thanks in advance for any suggestions or feedback - we have no dealers nearby with
a Focal surround setup, hence my reaching out here.