Followup:It seems all miles expiring by February 2023 have all been extended to March 2023. Saw a PTT post that seems to confirm EVA extended all miles regardless of whether you had any mileage activity or not:
https://www.ptt.cc/bbs/points/M.1651837534.A.16B.html
Not clear whether EVA will still do anything extra for those of us that did try to participate in the mileage extension campaign.