1099B - Missing Date Acquired or listed as "VARIOUS"

Hello.  I am trying to help my mother-in-law through her taxes.  Her Schwab Tax statement has a 1099 Composite that I imported into TTax.  When I check the Investment Income section, it shows that I "Need more info?".  The 1099 is missing 1b-Date Acquired and 1e - Cost Basis for these sales.

 

The statement has a section for Short-Term transactions vs Long-Term.  Is there a way to just use this ST / LT info and not need the actual date acquired (eg: enter a ST date - like 6/1/2019 and a LT like 9/1/2018 instead)?

 

I know the cost basis is a problem for the realized gain (and will have to figure out what to do there).  Just wondering if I don't need and exact date and can use dates that indicate ST vs LT for capital gain calculation?

 

Any advice?