Kurama has been proven to have only half his chakra. For one there is the size difference, kurama clearly shrunk, when minato sealed his yin chakra. So far in every case we have seen kurama, since then, we have seen him to retain the same size as after the sealing. Also the fact that when naruto uses kuramas chakra, he causes the mokuton to grow, ie full of lifeforce, which is yang. The chakra alone is a large proof of the yin not returning.
Saying that something that is sealed by rds will magically come back, is like saying oros arms will come back. Oro sealed his chakra into anko long before he was affected by rds. Yet that chakra became oro again, and still the arms were sealed. So far it would seem unlikely that you can regen or accumulate something lost by rds. Now kurama never lost ALL of his yin chakra. As it is said somewhere in the manga, all chakra needs to have some yang or yin chakra in the mix.
(meaning there is no chakra made solely of one type of energy.)
To kurama stealing narutos chakra. Kurama doesnt have to consume narutos chakra. He simply gains the ability to do so, and as the 8 tails said, if kurama had been consumeing narutos chakra during all of the war, then naruto wouldve been dead. Honestly we know very little about how the chakra absorbing works. As all chakras are said to be different, how does one change that chakra to their own? Honestly we dont know specifically how it works.
But simply to each their own...the manga has leaned heavily towards kurama not regen his chakra.