Option 3 (Chief Judge), with heavy leaning into Option 4 of ensemble piece (with lots of episodes not including him), followed by Option 2.
Forgive me if I'm wrong, but wasn't there the suggestion that Robo-Hunter was in the same universe as Dredd (ish)? Couldn't we go with the whole unshielded faster-than-light de-ageing a-la Verdus, which could be done behind his back? I'd imagine there's mileage in Dredd being robbed of his one chance at posthumous peace.
There's a few similar themes but too many contradictions as well.
Early Robo-Hunter mentioned Mega-City One in one narration box.
Slade took a zoom to Brit-Cit (both terms used in Judge Dredd) at the end of Day of the Droids.
The year that Slade went to Verdus was 2140, which was the Dredd year in stories published in 2018. The New York depicted in Robo-Hunter doesn't match up that shown in Dredd (people like Slade running around with weapons, etc).
To top it all, the Pacfic Ocean shown in a 2198 map (after Slade has died in 2147, been resurrected*, then naturally aged 51 years, then gets taken on a hunt for the Island of Doctor Droid) has a whole bunch of cities we've not seen in the Dreddverse, plus no sign of the damage from multiple wars.
Also there's the matter of two international Robot Wars which we haven't seen in Dredd.
* it's complicated.