It would likely be necessary to have an independent interpreter for the SQL dialect at least, yes. I.e. I assume that something that parses the SQL from scratch

It would likely be necessary to have an independent interpreter for the SQL dialect at least, yes. I.e. I assume that something that parses the SQL from scratch and then down the line hands stuff to sqlite as the storage engine would qualify, since the SQL dialect is the point of contention. (The "multiple independent implementations" requirement is afaik also not 100% hard - if everyone agrees to ignore it, it can be ignored, but it's a strong objection if someone disagrees)