First, one report does not an official announcement make, re: Liam and Elroy.
But if that is true: Elroy's drumming on the Neil Finn/Paul Kelly tour was outstanding, and I can imagine it working extremely well. I would rather it were an actual band, with Matt and Mark, but if it’s going to be Neil and Friends Playing Crowded House Songs, Elroy is as good a fit as we could want. See his drumming on Won’t Give In from Goin Your Way for a good example (I know it’s not a Crowdies song, but it’s a good example of why I think his playing works well with Neil).
Liam, on the other hand - he’s done good things with Neil live, but when he toured with CH in 2007, he tended to add extraneous parts to thinks which weren’t necessary (e.g. Mean to Me and World Where You Live do not need acoustic rhythm guitar), and made the songs weirdly busy mostly so Liam had something to do.
I would take Elroy over, for instance, Mick Fleetwood. Though if this *does* turn out to be the arrangement, then the early 2017 shows where Nick played bass were as much Crowded House as these will be. Hell, perhaps they were better as they also had the rest of Neil’s catalog to draw from.