Chasm Skulker does have some nice synergy with [[Tidus, Yuna's Guardian]], as you automatically get counters on it to proliferate
Its not worth speculating too much on Mondays changes, because that article goes live at the same time as this one does
With new sub-types of lands usually they only introduce a few and it's kind of meh, if there are enough towns you might be able to do neat things with them, there's already an obvious town commander in Wandering Minstrel, but they'll probably end up being pretty inconsequential there
A self-mill sub-theme with the likes of Patchwork Beastie and Fear of Missing Out could help a lot too, in terms of filtering through to the pieces you need
Maybe slap him with Voltron decks alongside commanders like Ardenn, Intrepid Archaeologist
You can see the spell grants a creature you control an ability that triggers when it dies and that ability makes another creature stronger