Senegals are, most definitively, a companion species! But, it's not what I consider one or the other, it's what they are classified under.
And yes, they do get easier as the years go by (if everything is done right, of course). Sweetpea hated all humanity when he first came to me and me in particular because he fell in love at first sight with Tobita, a female sennie I used to have, and she adored me so I was THE ENEMY! It took 3.5 years of multiple daily unrelentless attacks and another 1.5 for him to become my friend.