Hey toolw0rker! First - congrats for setting up Lookout, it can be super useful in a pinch and I think it gets overlooked often.
I didn't really know the answer to this - Lookout is third party software and our support details are limited, so I tried to find an answer for you by going directly to the source. From the looks of this question on Lookout's support site - What happens when Lookout finds a threat? - it seems like even if the notifications were turned off, there's a place in the app itself where you can view actionable threats after the fact. I couldn't find anything specifically calling out whether there are options for priority notifications - do you see anything like that in the app?
I see notifications every time a new app is installed, and periodically when Lookout scans all apps. It would be more annoying if I had auto app update turned on, but as is I update manually so get all the new app scan messages at once.
Lookout support advises "You can disable these notifications — you will still see any alerts for malware or any unsafe apps, as those are not notifications but popups."