Of those, I'd say only Anniesland and East Kilbride are potentials to be completed in CP6. Would think Barrhead - Kilmarnock will need more general improvements to track and signalling first, similar to Perth.
Hearing rumours that electrification to EK doesn't really gain anything performancewise so would be to remove diesel pockets rather than capacity.
Id think the EMUs would have better acceleration , clarkston up to Busby is a slog.