L2- EAD - Processing time and Stamping

Hi Anil,

My wife is currently on H1B with a maxout date in February 2020. She sent and L2 (I-539) and EAD (I-765) request to USCIS on September 2020. However she did not get any notice for biometrics date. We raised a Service request and the officer indicated that the status for the case is “systems indicate that on December 3, 2020 you appeared at the local Application Support Center and had your biometrics taken”.
Does it mean that USCIS has re-used an old biometrics ? - I still don’t see any update in the USCIS Case Status page.
Any guidance on the timeline for L2-EAD ? Her case was filed in Texas Service Center. Can her EAD be approved while her L2 application is still in progress ?
Her L2 visa is stamped till April 2022 in her passport. Can we travel to Canada border and get her new I-94 on L2 or does she need to go for a visa interview again ?

Appreciate your help.

Regards
Bharat