I have read the entire post you linked up and the "moving your inside" thread. (missing yet the explanation of the for legged "put animal here").
I think i manage to get some sort of that you call unity. In one of your comments you said that when you sense uke you have unity. Im able to feel throught a contact point; the tense up parts of uke's body, how his structure reorganizes when he react to my movements, where uke's balance is heavy loaded, his tiredness or degree of commitment. However Im not able to take advantage of this "unity" and manipulate it correctly without some degree of disconnection when I start a movement. I have a bad feeling on this, is like having something near but something with you cannot play and enjoy.
four-legged animal. it's a terminology i got from mike sigman. you and your partner when fully connected becomes a four-legged animal with whoever better at it will becomes the head section where you control the movement of the entire animal. sounded like you are not really connected or you are trying to overpower the connection. it has to be very subtle. don't know if you have seen Ikeda sensei or not. his approach is all about subtlety, not overpowering.
here is what i called the Ikeda 3-steps approach. you want your partner to move to the right.
1. push slightly to the right
2. then in toward your partner
3. then again to the right
so it's right-in-right and repeat in small increment. once you get used to that, then it will be just one step. however, methink, that you need to work on the internal connectivity more. i believed one of dan's mantra "aiki in me before aiki in you" and sigman has similar statement involved jin. you are trying to do the "aiki in you" portion.