I think ABV% should be up to the judges. There are some guides online for beer tasting and making the most out of a beer tasting session, which is what this judging is. I'm quite happy to write a mini guide if it helps, I've run beer tastings and have judged beer competitions, including a BJCP comp. I'm no cicerone and I'm sure there are members who know how to taste beer better than me, but would really like to share some guidance on tasting.
Beers need to be drunk from lightest flavour to strongest. Without having the beers before this can be difficult to know, so knowledge of styles is useful here. Lightest to darkest in colour, or weakest to strongest ABV is a good rule of
Have some crackers or some bland food as a palate cleanser, good to have if you have a particularly strong flavoured beer. Take a 5 minute break between beers if you need to, drink water between beers as well (this will also help the next morning!).
Each beer needs to be considered against a set of guidelines, not the previous beer you had. Whilst we're not using BJCP (or any) style guides for that matter, those guidelines can be your perception of that style. As far as I'm concerned, that's fine for the forum competition, so long as the beer is being compared to something more than the previous beer.