What welcome do the uninvited guests receive at the capulet’s feast?

They are actually welcomed. Nobody seems to mind except Tybalt. Tybalt confronts Capulet but Capulet will have none of it.

Content thee, gentle coz, let him alone. He bears him like a portly gentleman, And, to say truth, Verona brags of him To be a virtuous and well-governed youth. Act 1 sc 5