Normally, app to app communication in iOS is done via custom URL provided by the app. For example, Cachly has URL protocol cachly://......
i found a protocol for Offmaps but since Offmaps2 is a different product you would need to confirm with the developers that they support it or find out what they do support. This is what I found:
offmaps://?ll=[LATITUDE],[LONGITUDE]&z=[Zoom Level 3-17]&placemarker=1&placename=[WAYPOINT]
I expect this launches Offmaps with a waypoint using the name given at the designated coordinates.
You can trying building such a URL in Safari and see if it launches Offmaps2 as an initial test
gcbuddy seems to have a custom URL but details are sketchy.
Their support can likely provide more info.
Assuming you have custom URLs that do what you want, you will need to convince Cachly development to support integration with these other apps
In the meantime, you can easily copy the coordinates of a cache by a long press on the Coordinate text. Then you might be able to use the other apps with these coordinates by pasting them. Long press on the GC code in the title will copy it if they want the code.