I would bring the 2nd sponsor's completed and signed form along with the tax transcripts to the interview.
The CO may or may not ask for updated information. If he/she is ok with the joint sponsor's form without the 2022 taxes, then you are all set and don't need to burden your MIL. If the CO asks for the updated taxes, then submit the form from your MIL.
no one can really say
and Congratulations that u had all the documents for USCIS step as u asked for
The very best info could possibly be found on the Ghana portal looking at timelines of others
but the US embassy says this
Immigrant Visa (IV) applications are processed according to the Department of State’s prioritization guidance. Travel restrictions and operational constraints caused by the global COVID-19 pandemic have resulted in a backlog of IV cases. Recognizing how this backlog affects all of the thousands of families waiting for reunification, the consular section is not able to approve most requests for expedited IV processing, and instead works to process all cases according to their priority date.
The consular section and the National Visa Center will notify IV applicants well in advance of their scheduled interview. After receiving notification of a scheduled interview, please review and follow the provided instructions carefully to avoid delays in processing
According to other VJ members and the VJ processing times page, the average I-130 at the Texas service center is taking about 298 days. Looks like you have a few more months.