I have this same issue with either/both the BB and Aeros. Running each in isolation with the Ojai thinking it might be because the PS-124 that technically runs the show only outputs 1000mA max (so…unclear how it would actually power 4 pedals drawing 500mA?). Support at Strymon confirmed that the issue has to do with a self-protection scheme in how it distributes current; only wish I’d seen this post before purchasing this in May 
One issue we’ve seen in the past is that some pedals do not like how our power supplies ramp up power as a self-protection scheme. Digital pedals that are then connected see the low power at first and do not power on. A reset timer tells the internal processor to re-try powering on after a period of time. If this is too short, or not done at all, the pedal will never realize that the current has ramped up and is adequate to power on the pedal.
We have found that running pedals that have this issue with a current doubler (NOT voltage) will provide enough immediate current to power our some pedals that have this issue. However, this does mean you would need 2 outputs to power just one pedal. We unfortunately have not been able to personally try it with your specific pedal, but it’s something you can safely try to see if that helps, as more current will not damage a pedal.
The reason that we think this issue happens with the Singular Sound pedals isn’t due to a lack of overall power. It’s a lack of initial current to the pedal. Like I said in my previous email our power supplies ramp up to the total output of 500mA per output. There are pedals that won’t work if they don’t receive the full amount of current right away. If they don’t have a way to recheck for that signal with a timer then they won’t turn on.
It’s rare that this is an issue, but there are some pedal manufacturers that experience this issue with our power supplies.
As for the total amount of pedals that can be powered by the Ojai, it depends on the pedal and the voltage.
At 100% efficiency, each of the outputs when maxed (9V, 500mA) uses 4.5W of power. Electronic devices are never 100% efficient however, so running at a lower efficiency could actually use more than 4.5W of power per output if maxed.
The formula for watts is amps x voltage. 9V x .5A = 4.5W.
We don’t offer any power supplies that output above 500mA per output.
Changing the 24V power adapter into the Ojai won’t change anything. The design stems from the Ojai, and not the external power adapter.
I wasn’t able to get the Aeros to start reliably using the current doubler cable; didn’t bother trying with the BB as I can’t use the Ojai the first anyway.