How long it takes for L2 extension approval after L1A Extension is Approved?

How long it takes for L2 extension approval after L1A Extension is Approved ?

This is a very hard thing to say…The reason is with the New Biometrics Process, it can take long. It is same for H4 as well. Many users have shared their inputs at article in the comments, it applies to L2 as well. You can read the same to get an idea.

The biometric process is completed already for my spouse. Will it still take longer ? / uncertain ?

It is uncertain…it is definitely longer than previous times. Check the article and the comments, you can expect similar timelines as users shared for H4