The 18th edition states in the preamble the date at which the design must comply, so not complying with any of the requirements after that statement is only required for designs after that date, so to comply with the 18th edition the work only needs to comply with the requirements required at the date of design. Yes that does mean the inspector would need the design date, however the inspector is only looking for potential dangerous for code 2 and no edition of BS 7671 has allowed anything potential dangerous.
Also you are only inspecting electrical items installed so missing smoke alarms or lights does not generate any code, even if no lights in the house, that would not generate a failure, although clearly the premises would not be considered as habitable.
As to sink and socket distance, seem to remember the 14th edition did list a distance, idea was a kettle lead was of a length so it could not be left plugged in while filling, however at that time the wiring regulations were like today's regulations and the on site guide combined, and seem to remember one edition where metal window frames were to be earthed, and one where all items in bathrooms were bonded, so whole idea of the EICR is to remove potential danger, or danger and to inform the owner if things will need upgrading before other electrical work is carried out, however the EIC can't be issued by any one not in control of the work being done, so the EICR forms are used to inform the LABC if the work complies with the BS 7671 if it was being designed today, so the extent of the inspection and what codes are used depends on the instructions given to the inspector. So if the LABC says to an inspector this is a new extension or a re-wire will you see if this work complies with requirements for a new installation the inspector can clearly include new requirements like need to fire resistance consumer unit, forms are the same, it is the instructions to the inspector that matters.
All 230 volt electrics are potentially dangerous, so it is impossible to say awarding a code C2 is wrong, the form was never designed as a house electrics MOT it was designed to tell owners the condition of building electrics, and the code 4 which said does not comply with current edition has been removed, as it was causing problems where people thought they needed to up grade the building electrics just because a regulation has changed. In some cases up grading may be required, for example if the boiler is changed and new ones manufacturers instructions say it needs a type A RCD of 30 mA unless you can show the manufacturers instructions are wrong then it needs upgrading, however this should be advised by person fitting the boiler, not left to next EICR, it would be impossible for any inspector to know which boiler requires a type A and which required type AC there are just too many.
As to items like electric car charging points, since most need type B RCD and some can use type A then clearly with a type AC the inspector would realise this will not comply and not really worried about looking back at previous issues as back in the 14th edition time the charger was fixed to building the the vehicle, so he could clearly use the latest edition of BS 7671. However to date I have not seen a single complaint of an EICR having a C2 because of the wrong type of RCD being fitted. Wrong tripping current, or time delay may be but not wrong type.
What I would like defining is "permanently fixed to the building" I would consider an immersion heater included in an EICR but not the boiler, I would expect a boiler to be covered with the gas safe inspection not the EICR, however there is nothing in the law that says that, so should an EICR inspector remove the covers of a boiler in the same way as removing a selected number of sockets to check for grommets, and connection of earth wires etc? The remit of the inspector does seem to be wide open for interruption.