Sky Sports claim a £1m deal has been agreed between PNE and the Saints for 21-year-old McCann.
Murphy is said to be coming on a season-long loan.
Although the transfer window shut at 11pm on Tuesday night, clubs have until 1am on Wednesday to complete moves if a deal sheet is submitted.
If the deals are done, it would take PNE's summer recruitment to eight players.
Earlier in the window, Sepp van den Berg, Liam Lindsay, Izzy Brown, Matthew Olosunde, Jamie Thomas and Daniel Iversen signed.
Thanks for reading. If you value what we do and are able to support us, a digital subscription is just £1 per month for the first two months. Try us today by clicking here