If past precedent (and East Yorkshire's 350 plans) are anything to go by, Good Friday will be a normal Friday service by Stagecoach in North Lincolnshire. The 255 will presumably depend on Wren Kitchens plans for the day. Usually normal Saturday and Sunday and Sunday service on Easter Monday.
The Hornsby operated Barton Town Service usually operates as normal on Good Friday as well.
I seem to think North East Lincolnshire local services are normally a Saturday service on Good Friday, with longer distance services a normal Friday service - although on some routes there is little or no variation between school holiday weekdays and Saturdays. Meanwhile local Stagecoach services in Hull are normally a Sunday service. All down to differing historical norms, but I think Good Friday sees more area-to-area variations than any other holiday throughout the year.
Thanks very much for that HT. Fits with my past recollections too. NE Lincs seems to flutter a little from year to year with regard to Bank Holiday services so I always like to hedge my bets.