With full knowlege from other posters in the past concerning the 7th, I don't lay a finger on any of those ships.
I use the initial renown to "buy" a solid IWO (watch and mach skills), do my couple of days sailing around till I transfer to the 2nd after the radio message to return on the 4th.
Go to my new base and "buy" the improved hydrophones with my remaining starting renown and start out on my first war patrol.

There is no down side to not attacking those "target ships" ect.