To complicate things even further the US have thrown their hat into the ring.
Navy Hopes for Commonality – Or at Least Interoperability – With Frigates in Australia, Canada, U.K. - USNI News
It is a pity that the US isn't considering the Type 26 themselves. Imagine the saving involved if these close allies built 50 or 60 ships to more or less the same specs.
I read the USNI article about a week ago too, and the 'headline' is a bit misleading.
Once you get into the article its a different story, the relevant quote to focus on is:
"CAPITOL HILL – The U.S. Navy is in talks with Australia, Canada and the United Kingdom in the
hopes that all four navies will design and field frigates with common combat systems – or at least interoperable ones – the deputy assistant secretary of the Navy for ships told USNI News."
Now even 'if' all nations selected the same basic hull design, for example with the UK and Australia at this stage with the T26 (and possibly Canada), and the US suddenly adding T26 to their Frigate competition, each nation will end up with completely different sensors and differences in weapons and weapons systems too according to their own preferences for weapons and sensors that support their own industries, etc.
Just look at the differences in the UK and Australian configurations, Canada (if T26 is selected), will no doubt be different again.
I can see all four nations using different radar systems, and a variety of CMS, I can't see them all using a 'common' CMS, but I can at least see them all heading towards being 'interoperable' with each other.
To me the solution is having an appropriate 'interface' that can pull all of the CMS data from one nations ships in a format that can be transmitted and received by the other nations ships, and visa versa.
Maybe if each ship is fitted with Cooperative Engagement Capability (CEC), as the USN has and is also being installed in the Hobart DDGs, that could be the way ahead (and of course you need the appropriate interface between each nations CMS and CEC.
Anyway, just my opinion of course!
Cheers,