I think it will be the Germans. They have run a tight race. They have been talking to people on the ground since before Collins. They hired all the key people right off the bat to run with. This isn't their first party. They have broad relevant experience to execute a project like this. They have been hammering price, capability, local build, low risk for years. Of anyone they are probably the only ones that can pitch an international submarine facility, which is the sort of stuff will get them home, local build content and local work. I think they have looked at what the RAN wants the most and tried very hard to meet that requirement (what they were burned on in Collins?). 60 Bunks, 10kt cruise with <20% indiscretion rate, lithium batteries, optional AIP with a 20 day endurance, multi-purpose lock for vertical launch weapons or personnel. To be honest they were the benchmark to beat.
The Japanese, while I think offering a very (the most?) compelling/complete out of the box platform, aren't quite ready to walk in and sort the shit out and provide a fool proof solution for the build. I think this has been too much of a learning experience (to beat the germans). I wouldn't rule out Australia and Japan sharing submarine technologies. I imagine this will be the silver lining for the Japanese if they weren't selected.
The french have been on their own planet a bit. But the proposal has compelling performance metrics, in a performance comparison they would score high (IMO from whats available). Risk, experience, costs would be weaknesses (IMO). The french fired pretty much their entire sub management team and started fresh about 12 months ago due to delays. But if you want a conventionally powered SSN that is pretty much what they are offering.
Arguably all 3 are offering the most amazing conventional submarine ever built. Which ever we choose I doubt the capabilities will be disappointing. Which is probably why there is a lot of pressure on low risk, on time builds.