1. Gakido absorbs chakra to the users directly replenishing their chakra, Sasuke put the chakra in susano'o not himself. Therefore it's not a Sasuke's rinnegan absorption power considering the fact that the chakra was extracted not absorbed.Its classified as the 3rd MS power and sasuke used his rinne to control the tailed beast chakra combining them.
Preta
Coat
psedo gezo mazo
Whatever you want to call it its both ms and rinne combined
2. COAT is a shadow and light style technique not a rinnegan technique, Kurama said that Sasuke putting the chakra together is the reverse of what Hagormoo did to separate it. He was complimenting his biju level chakra control not stating to use COAT. COAT is a technique that creates sentient beings out of chakra alone. Sasuke's humanoid-lightning chakra is not sentient.
3. Pseudo Gedo? I don't know what you're talking about here so I can't respond.