I have seen online "suggestions" about the 99021-99030 being built with ETS but it is probably supposition, and I would have expected GBRf to have specified it at the contract stage. However, I believe there is a gap between building the first few of the class, and the rest, in order for tweaks to be made o he design, so maybe that could fit.
It might make sense for the 99s to be deployed on the caley sleepers, so if they are receiving ETS for the Mk5s, I imagine they would fit the full shebang rather than "lite" for north of Edinburgh. It would provide considerable flexibilty to GBRf / CS in situations like last night when the four sleeper trains were turned round and sent back due to a line blockage. For example, if operated by ETS 99s could the northbound trains turned right at Warrington and run "non stop" to York then up the ECML into Scotland, and vice versa. vy ha trains