The DMS for the Aurora and MDMS for Cyclone are not the same. The share the same history, but the way Canada writes requirement ensured they wouldn’t be.
Even though if they had met the intent of the requirements, not how they were technically written, they would be the same…
The hard part of any link is not the box (especially 16, as it includes the radio) it’s the software. Same with AIS. The integration is what takes effort. The implementation and use of Link on the Cyclone (and historically, the Aurora) has also been hampered by community misunderstandings of what it is for (to support commander decision making) and how it achieves that (a common operating picture, not just sharing data).
But as you said, that software exists in the Aurora. Luckily, it can be “moved” to Cyclone, given resources (time, people, and money).
There are options for range extension over HF. There are also options other than JREAP-C for range extension over SATCOM. There are multiple SATCOM options, and there are requirements and opportunities for SATCOM with Cyclone other than range extension with the ship.
I do agree with you somewhat, though. The range extension issue assumed single helo over the horizon. As we almost always operate as part of a force and other units could provide Link-16 relay, that requirement was probably over stated.