A lack of active mining pools would be an indication that a coin is not being seriously mined in anyway. It's fairly easy to check pool stats. That combined with a missing developer and little to no trade volume would also indicate it's not being mined seriously.
I think I can discern the main criteria:
Minimally, a candidate altcoin must be PoW-only and listed on some arbitrary exchange. fallingknife keeps a reasonably up-to-date list of exchanges but obviously, only those of which (s)he is aware. I recommend that you address the woolliness of the other criteria: not being seriously mined, little to no trade volume. In practice you will need actual numerical values, a likely contentious subject.
Edit: the volume is at least partly satisfied, defined as: under 0.2 BTC weekly AverageThe meaning of a missing developer is very unclear, there are a lot of unwarranted assumptions in those three words. Apart from the difficulty introduced by the fact that the notion of a developer is somewhat anomalous in the context of a peer-to-peer network (there is no practical means of enforcing the notion of an official anything), the use of the definite article incorrectly presupposes: that an altcoin must have at least one developer to function, that a developer must be identifiable as such in order for the coin to function, that the identified individual conforms to some as-yet-undefined specification of acceptable, etc, etc.
The task becomes even more challenging when considering the assumptions behind the term missing and how difficult it will be to operationalise them as criteria when they are so vague and unreliable (missing from where exactly? How long is too long?)
I recommend you undertake a paper-and-pencil public pilot project which at least touches on as many of these issues as possible so everyone can get a sense of the likely scope and range of application of the principle. Something from the tail end of coinmarketcap's listing that fits the criteria would probably do, or something with low trading (where the term low is defined in numerical coin/time terms) from Poloniex listing (as they have a reputation for not delisting --- but by the same token, ignore anything on Bittrex as they regularly cleanse their listing, something which C-CEX has also started to do). If handled sensitively, the very task of publicly selecting a candidate alt for this exercise will probably reveal any substantial disagreements and provide a context for resolving them (assuming they can be resolved).
Cheers
Graham