Paul the belt sprocket is keyed but dont windy gun the crank pully bolt off , there is a hole to lock the crank where the exhaust goes under the sump , just put an m8 bolt in to lock it

Never had any issues with DV4 crank sensors mind , wiggle connector with engine running but i wouldnt hold much hope

Egr on these are a standard vac operated diaphragm so and the crank sensor code is likely to have been flagged due to it cutting out . I dont have any experience with the scanner you have but if you can see fuel pressure actual over desired then give it a good road test and look at the figures
Other things ive had is wiring to rail sensor chaffing in the hard conduit , try flexing the harness from ecu to FPS , its not a long section

Hth's

Steve

Steve