IMO, this case is a perfect example of why the 5th manner of death exists: Undermined.
I don't think authorities can state unequivocally that the family was intent on spending more than an early morning hour in the cove on their Sunday outing with their beloved baby and dog in tow.
I also thought Sheriff Jeremy Breise was very convincing on 8/20 when he initially cited they were taking it slow, first investigating any mines in the area, and toxic algae bloom. Adding that the family had a small quantity of water when recovered, IMO, there wasn't even a hint during the first presser that hyperthermia was being considered as the leading cause of death. I'm sure heat exhaustion was discussed on WS long before it surfaced in print!
Personally, I think it was probably the Sheriff's earliest demeanor that caused me to gravitate towards lightning as the cause of death. (See 2 min video at the link below). While I accept that hyperthermia/heatstroke killed the family and their dog, I'd be more comfortable with this finding if it was introduced earlier as the most likely cause of death but that investigators also wanted to be thorough and continue to eliminate any other possibilities before making a formal announcement.
MOO
https://www.fresnobee.com/news/local/article253616898.html