Do the fibers appear to interdigitate (connect with each other) at specialized junctions that appear as occasional, thicker, dark bands running perpendicular to length of the cell and interrupting the striations?

No.

Explanation:

Fibers are contractile units in the muscles. They are surrounded by plasma membrane called sarcoplasma which is made up of muscles cells cytoplasm. Fibers are sometimes stratiated caused by lighter bands composed mainly of a protein called actin, and darker A bands composed mainly of myosin. Fibers do not connect with each other at specialised junctions and do not interrupt striations.