As for Jesus calling God His OWN [ιδιος] Father, thus, making Himself equal to God - it is well-known that the Son of God is called the "only-begotten Son of God." This is to distinguish him in some way from all others called sons of God. Since he is also called 'the Firstborn of creation' and 'the beginning of God's creation,' we can see that God Himself must have created ("begotten") him first and all other things were created by God through the Son. So, since Jesus is the only person created personally by God Himself, he is, in a special sense, able to call God his OWN Father.
[Notice the use of isa (“equal” at Isaiah 51:23) in the Septuagint: Here God is speaking about those oppressors who commanded Israelites to lie down flat on the ground so they could be walked upon, and the Israelites “made their bodies equal [isa] with the ground” so they could be walked upon. Obviously the Israelites did not make their bodies absolutely equal with the ground thereby making themselves literal ground [or having the ‘absolute sameness of nature’ as the ground as Walter Martin would have to say] also, but merely made them equal in the external attribute of the ground: flatness, lowness, etc.]