I can't find anything procurement related unfortunately. From what I've heard (via DTR and by ear) the boats will likely go to 2RAR as a means to insert/extract personnel over greater distances, at higher speeds and with suppressive fire should they be in contact.
Link to DTR issue wrt 2RAR wants/needs:
Australian Army considers cannons for air defence Third Air Warfare Destroyer in the water Hawkei manned weapon station French unveil new 6×6 combat vehicle US special ops acquiring new glide munition Spike LR2 selected for Land 400 UMS Skeldar to offer V-200B UAV to RAN NASAMS Launcher Vehicle...
dtrmagazine.com
(On a side note, I believe some SOV-Cdo have been running with 2RAR as of late. Would be interesting to know how they are using that and how it's going).
It is certainly an interesting subject. Depending on the characteristics of the boats selected, I would be interested to also see the RFSG utilising them in the Top-End, CYP and Torres Strait for actual riverine patrol as opposed to supporting the amphibious force, as I expect would happen under 2RAR.
There have been changes in the past four years to the IIP however. Other capabilities/concerns may have popped up for procurement decisions elsewhere (e.g. Land 8116). The RFSG seem to make do with their tinnies and quite frankly it is perhaps a better piece of kit for the role they do. I'd argue 2RAR needs them, on the other hand, as they could do with the capability to insert/extract with organic direct fires - a Zodiac isnt going to cut it if they are bumped and RAN RHIBs have their own takings.
In terms of what platform, can only speculate. Engagement with AFoP SURC boats a few years back gives an idea of what defence may be looking for/towards, though I have heard other things related to SOC-R (seems unlikely, personally).
Will look to find something document/article related, as opposed to snippets.