Hello Ark and welcome!
First and foremost, and I know the HA's will agree, I would not do anything different than what your MD recommends when you are on the full fast as he is the professional. If my understanding is correct, the two cups of skim milk pretty much equate to another two shakes (minus the nutrient content) and will not hurt you or put you out of ketosis. As a matter of fact, 8oz of skim milk is recommended to help maintain ketosis safely if you are ever in a crunch and run out of products while waiting for a shipment. Now, having said that, while the protocol for the full fast used to be FIVE shakes/supplements a day, it has since been changed to SIX shakes/supplements a day. people eating a lean and green meal daily now have five supplements. I am unaware from your post as to whether or not your MD is aware of this and due to the two cups of skim milk has you staying at five or if perhaps you should bring it to his attention. So long as you limit yourself to one bar a day and follow as you have been doing, I would venture to say you will remain in ketosis just fine. Do stay under your MD's care though, while doing the full fast, and perhaps ask him about adding another shake?
I hope this helps. Best of luck with your weightloss, I would say 4-5 lbs a week is fantastic and you are on a roll. Looking forward to hearing all about your journey and getting to know you along the way!
-M.