Are these foundation issues significant?
-#1 This seems a little odd.  Not sure how old the house is but all houses will settle.  But it seems like there is a crack and one side raised a little.  I would have to see pictures to give you a better answer.  

This is an issue.  If this house is 50 years old and it happened 45 years ago and there is no moisture concerns then not a big issue.  You could fix it by taking out tile, leveling floor and retiling.  Not a small job but not "major" either.  Now if this crack is new or there is a possible water issue because of the crack (given your area probably not but you never know) then yea maybe it is an issue.  Also if there are land changes and the concrete is being pushed the buckling/crack could get bigger.  This still might not be a "major" concern but could cost a few thousand to fix.  I would need to see a few pictures and more details on house.

-#2 This is nothing.  Minor cracks in ceilings are from movement and can also be caused by drastic changes in humidity or temperature (that is why popcorn ceilings were used in desert areas).   The fact is if the house humidity levels get too low the gypsum becomes more likely to fracture - and at the same time the low humidity levels would cause the structure to shift slightly.  This is nothing.

Would I buy the house?  I would need to see pictures of floor to give you a better answer.  Also if I was already thinking to myself either of these I would probably get it - the floor issue is barely noticeable and looks fine or the floor is old anyway so I could level it when I rip it up.