I've just had a look on RTT and from the timetable change, everything is now showing as class 185 timings. Except that is for a few ECS moves. Some passenger services miraculously change to LHCS when they move to depot after terminating. Clearly the info on RTT isn't yet fully updated to reflect what is actually going to happen as regards motive power, but it does seem clear that there is generally going to be a 2 hourly SCA - MAN service with a 2 hourly SCA - YRK in between.
The reason all the South Route workings are shown as 185's is because there are no SRT's in the system for the timing load used by NR/TPE for the Class 68 workings other than between Doncaster EPT & Doncaster station, if you look at the Class 5's from/to Doncaster EPT you will see that they change timing loads at Doncaster station to/from DMU to/from Diesel Locomotive.
Basically, a schedule (especially a WTT one) cannot have missing SRT's therefore you have to use what's already in there which in this case is the timing load for a Class 185.
I'd imagine at some point in the future the SRT's for the Class 68 timing load will be input into TPS as they were for the North Route
On the Scarborough route it's as you say 2 hourly through to Manchester from the 06:48 until 16:48 then 19:48 & 22:45 which gives 8 through workings, there are a couple of Scarborough to Leeds workings at 17:48 & 18:48 ex Scarborough, the rest are Scarborough to York services.
All Scarborough line services are booked for Class 68's & Mk5a sets.