[mothered]

Is it possible to use the sealed box method for 2 different items in the same order?

I'd stick with just the one Item.

Customer dissatisfaction Is unlikely for two different products on the same order, hence It may raise suspicion to the point of thoroughly checking each return.

Is the warehouse that receives the goods scanning the packages to check that the product inside looks like the product in question?

If you've resealed the box to perfection without any Inconsistencies whatsoever, there'd be no reason to check Its contents.

Also see if I can take a motherboard and replace the original with an old one?

Are you still referring to the sealed box method?