There are quite a few reports out there from reputable firms such as RWDI that do confirm that in certain configurations and layouts that the design snow load is not affected. These are specific to racking manufacturers. I do not have any I can put my hands on or share at this point in time. Reputable solar racking manufacturers get reports completed for their systems that confirm design snow and wind pressure information that is useful to structural engineers. Whenever I have worked on a roof top solar project in the past, we require the solar manufacturers (typically the racking suppliers) snow/wind report for their system before we will start work on the project. If they cannot produce a report, we do not do the work. They grumble at getting the reports completed as they are quite expensive, however, it is just another cost of business that they need to account for if they are going to complete their projects properly.
Racking layout must be considered, as does ballast layout for ballasted systems. You are correct that the point loads and their effect on the loading the roof structure must be considered.
There are many, many engineers getting the snow/wind reports, accounting for point loads, etc.... so don't let the solar people tell you differently. I do find that there are solar companies that just keep calling around until they get the engineer that is willing to sign off cheaply, without reviewing any background info, nor requesting reports, likely due to unfamiliarity with the in's and out's of this type of work. I would not recommend being that engineer.