Don't confuse mandatory, with the examiner looking for evidence that you are reasonably diligent and well across your preflight planning to a safe standard. That isn't to say that he is about to ask you about that particular graph, just that it is something that one ought to use when doing a diligent fuel plan. If your fuel plan says something like 10 litres start and taxi, 20 litres climb and 32 litres per hour thereafter then he will see hat you have considered it properly (and know how to use the poh). That kind of thing sets a good impression before you leave the ground. And for extra points replot the Cof G for either zero fuel or expected landing weight to make sure it is still acceptable. All of that stuff you can do the week before the flight if you ask the guy for his weight.
The 1157 is a checklist / tickbox form to ensure the reasonable conduct of the assessment, its not 100% prescripitive. Nitpicking, it does say, "preflight Including documentation... ", the use of Including, means, all items of preflight including but not limited to docs etc. And the mandatory marking is a reminder to the examiner, not an instruction to you. If you look in the instrument section, you will see an instrument approach to 200ft is marked mandatory but you won't be doing one ! and you might have to do a few minutes under the hood so you may be using the instrument flight section.
Leaving all that detail aside, you are unlikely to struggle with a re-validation if it is only a few years and your original training was good. The flying itself is less likely to be a problem than procedures/documentation/memory items etc.
General good habits for any checkride include; printing at least some of the weather off, a written w&b, a flight log with fuel plan, having a briefing ready for the examiner in the aircraft and on departure, looking over the local area chart and a read of the POH. Also, of course checking that the mandatory parts are done, eg Notams, Medical etc. Cleaning the windscreen is always a good way of scoring early points. Knowing the current fuel state of the aircraft beforehand and having a max fuel level in mind if you are likely to be close to max weight is of course good.
One might expect an inflight emergency requiring a bit of fault finding/commonsense. eg smoke from the radio stack or ALT master tripping.
Hope that helps ...