Are there any updated plans to support OCO WL strategies? OCO functionality has been available on the Fidelity website for over 5 years now, but haven't seen anything in WL to support it.

Nice to have! :-)

Bracketed exit orders have been supported for years too, but OCO entries are used so infrequently in strategies that no one has even started to think about it. In general, new features that fewer than 10% of the user base are expected to use simply don't have a good chance. But I encourage everyone who wants this feature to call their Fidelity rep and petition for it.

Time to revisit this topic.

The WealthSignals tab offers a "Add Signal" with a text entry field for "One Cancels All (group name)".

How do we programmatically set this field?

If not currently available, when will it be released?
If available, how does the WLP engine treat the OCA field in strategy simulations? e.g. WLP will need to respect the OCA with regard to SetTimeOfDayPriority helpers for more accurate backtesting.

The related to this question is: How about programmatically setting the "Good Til Cancelled (GTC)" field? (also observed in the "Add Signal" drop down.)

The thing is that since OCA orders were implemented on the WS backend independently, the WealthSignals OCA doesn't have anything to do with Fidelity's backend or Wealth-Lab engine. No programmatic setting of GTC/OCA is supported: it's solely a WSP (WS Publisher) thing.