As I see it, the issue with integrating a missile or weapon system into a new/another CMS is not so much whether it can be done, but more about how much it will cost, how long will it take, and would a prospective buyer be willing to pay for it or not.
If (big IF) Australia were to seriously look at adding Sea Ceptor into/onto the Canberra-class LHD's, that is a pair of vessels running some version of the 9LV CMS. With the five Visby-class corvettes (are they really corvettes, or large patrol boats?) that might make up a total of seven vessels running some version of 9LV and CAMM missiles, hence the question about cost.
Its not just about cost. But its a factor.
It's about sometimes you can avoid the cost almost completely by letting someone else go first. This makes it much worse, because you look wasteful if you commit to do the integration work then someone else just comes along, or you can even end up with parallel integration programs doing the same thing, reinventing the wheel separately. Also a badly designed program can lead you down dark paths of orphaned systems and incompatible un-integratable or un-upgradable systems.
In this case. Sweden is fully committing to CAMM and 9LV.. They are going to pay basically all the integration costs and handle the risks themselves. Not that surprising, SAAB is swedish, its a local program they can do, CAMM probably the best missile to fit to something like the Visby. They are quite far along with this, again its very important for them, and undoubtedly by not integrating CAMM earlier, they aren't seeing many sales of new 9LV either (Canadia and New Zealandia both abandoned 9LV). Sweden is in europe, plenty of CAMM knowledge around there, and supply.
Once integrated on the Visby, the integration costs and risks for any Australia program is much much less. All the software/electronics stuff if basically done, you just need to do some localisation and the mechanical and structural modifications to physically fit the system. You fast follow someone else who has dealt with all these problems and your program is much cheaper, faster, lower risk and often with better outcomes and better execution.
So you just pay sweden a fix price licence for software, and pay a bunch of consultants to share their info, and it becomes a much happier bolt in solution. While not quite that simple, it's a heck of a lot easier than selling a complete integration from scratch to politicians who then need to spec out with Brass an actual achievable project about a missile we don't have much operational expertise with.
The Visby integration is particularly interesting as they aren't just using 9LV. They are also using SEA Giraffe. So the whole command and sensor loop will be integrated and transferable to the LHDs. So in this case, might be best not to put CEAFAR stuff on the LHD and keep the existing Giraffe setup. Giraffe is quite good, its what the Anzacs used to have, and the modern Giraffe is very good.
I imagine we were also hopeful that the Turks were going to spend some integration money on the LHDs, but theirs are so different there isn't a lot of commonality structurally, layout or electronically. The spanish also don't appear to be spending any money on the LHDs. The Turks were meant to fit Phalanx and RAM, but the Phalanx needed its own "tower" to be effective, completely changing a lot of the ship to do that, and the RAM launcher appears not to be fitted, possibly because of where it would be located would cause significant issues trying to use the RAM launcher while handling aircraft of having anything or anyone on deck as it is right near the "primary" rear lift and parking areas around it..
If ExLS low-profile CAMM could be fitted, we could probably keep the existing 25mm typhoons, which are still useful.
While it would be a new missile type, CAMM is pretty good, and already in use with the New Zealanders and UK. We could collaborate on war stocks, and any future NZ combatant, perhaps built in Australia, could have CAMM as we would be very familiar with it.
While often compared to ESSM, its not its natural competitor. The natural competitor is RAM, and the RAN has no RAM. CAMM would be ideal for smaller ships or auxiliary ships, its cold launch and compactness makes it for easy fits. With so much talk about bolting on more missiles, a CAMM launcher would make a lot more realistic sense as physically it's possible to do that. Bolting 50 tons of mk41 isn't (particularly onto an OPV or landing craft). With 9LV it would make it low risk integration. With it operational on the LHD, we could then looking at integrating Ceafar and CAMM and 9LV, again, much of the risk would be mitigated and it could be expanded to any combatant. Nulka launchers could disappear and it be fired from the ExLS making it a neater solution, freeing up deck space.
ESSM also has another issue. The nature of the program is multinational, involving unreliable Canada and crazy Turkey. Turkey disruptive status could be a future risk and also about having a completely sovereign ESSM production program may not be as easy as first appearing. Also if a hot war ever happens in Asia. ESSM is going to be gobbled up at a fantastic rate, possible more than SM-2 or any other missile. Having something else in the pantry, second source, possibly with some sovereign capability Could be useful, at least integrated. While not ideal as a ESSM replacement, its sure is a hell of a lot better than just 20mm rounds.
Again this is a reason why countries need to make defence spending a priority. Australia's capabilities are kinda depending on Sweden's integration. Sweden Cancelling the follow on Visbys kinda stuffed up a lot of 9LV integration stuff. Probably why other navies started to abandon 9LV or augmenting it. Undermining their defence capabilities and programs. Instead of force multiplying, you are force dividing.