Constellation Schema; Relationships between fact tables
Not really. Fact tables has rows which are a intersection of all the joined dimensions. Joining a fact table to another fact table doesn't really make sense - two facts should be joined through a conformed dimension.
I don't consider it acceptable.
No. Measures quantify the intersection of all the dimensions, they enable you to measure that item not change the granularity or definition of that item. That is what Dimension tables are for.