Thanks to Kasol and CompanyMan1 for your thorough replies. The details you provide were lacking in my search. Knowing the shoe contains a check valve puts it all together, and the pig “landing” on the float collar puts those pieces together.
For those of you who worked many nights through to kill this well, know you are deeply appreciated by many of us, up here in the north. We have been praying, without ceasing, for your safety and success. May God continue to bless your work in the placement and proper curing of the cement plug(s).