The confusion has arisen because of the structure of the sentence. Both ‘due to’ and ‘because of', being prepositional phrases will always be followed by a noun or noun phrase; but that does not mean that the prepositions modify that noun or noun phrase. . Therefore, let’s flip the sentence and see what modifies what.
Jeremy, along with five of his best friends, is attending the grand opening due to the generous invitation by the host
Jeremy, along with five of his best friends, is attending the grand opening because of the generous invitation by the host
It is clear now, Jeremy together with his group is attending because of a generous invitation. You can see that what lies before 'because of ' is the verb "is attending ".
The inter changeability test between ‘due to’ and ‘caused by’, is a litmus test, that should be necessarily passed to be taken as right.
If we were to rewrite this sentence using ‘due to’, perhaps the following would be the one
Jeremy’s attendance, along with five of his best friends is due the generous invitation by the host; here due to modifies the attendance.
But aside from refreshing some tenet of grammar, are we supposed to test the veracity of the non- underlined part in SC?