Mccalls 7117 pattern and alterations Sewing Machines Parts and Sales in Los Angeles

I’m attempting making this pattern (a dress) and i was reading over the pattern before I make the commitment of cutting my fabric. The pattern has four separate views (for anyone who has it as reference it’s view D), I’ll be making the one with a full yoke. According to the pattern the dress is self facing in the bodice, but not the yoke. I’d like to extend the lining up the yoke to join at the neck and armhole edges. The neck and armhole edges are encased in bias tape, so the lining would need to join there. What I’m really looking for guidance on is if the lining meets the garment fabric at neck and armhole edges, should the fabric raw edges be encased in bias tape or should the tape be applied to a finished seam?

I’m also unclear on what is required when it asks me to understitch a seam, could someone give guidance on that as well?