Based on my understanding of the (unconfirmed) salary cap for next season, scholarship players won't exist, so that puts us at 16 Senior Players currently. LBS out, Hollman in keeps that number the same.
With 4 visa players in the expected spots and using the 4-2-2-2 Geeeny ran last season we're probably looking at the following squad:
GK: Henry Gray, Alby Kelly-Heald & Eamonn McCarron
DF: Isaac Hughes, James McGarry, Bill Tuiloma, Matt Sheridan, Lukas Kelly-Heald, Xuan Loke & Jayden Smith
DM: Visa #2, Corey Hollman, Fin Roa Conchie & Anaru Cassidy
AM: Kazuki Nagasawa (V), Visa #3 & Nathan Walker
ST: Visa #4, Visa #5 & Corban Piper
Which makes a squad of 20 players, leaving 3 spots open.
One definitely has to be a Striker, as currently Piper is the one and only sub, so it would be good to have a back-up/second sub.
Second probably AM as the LBS replacement. Walker is currently our only sub for this position and spent last season out injured. I believe Roa Conchie can play up here if needed, although I still think another option would be good.
Last one is probably has some more freedom. Could go for someone like James Bulkeley as an extra defensive back-up. I'd probably look further forwards for another AM/ST option just in case (tend to see more subs further forward). Could also go for another option in the DM spot as it doesn't seem like Cassidy was in the picture much last season. Rogue option is to save it and see if you can bring someone in during the Summer window (e.g. Riley Bidois or Kyle Adams), but that's probably only if the Nix are confident in getting high quality over any options they could sign now.