So, Easter" in the KJV is correct?
When Tyndale meant Easter to be the same thing as the Passover, yes, originally, it is correct.
"And shalt be" in Rev. 16;5 is correct?
Yes. when it is how Jesus is when He judges which is the same in the future.
The omission of "through our Lord Jesus Christ" in Jude 25 is correct ?
That's a new one that you had brought to my attention.
The KJV has it right because Jesus Christ is the God and the Savior.
Jude 1:25 To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen. KJV
Jude 1:25 to the only God our Savior be glory, majesty, power and authority, through Jesus Christ our Lord, before all ages, now and forevermore! Amen. NIV
NIV makes it look like how God is the Savior by using Jesus Christ as the means for how He saved others. No wonder believers are denying His deity. According to the Textus Receptus, there was no dropping of any Greek words in that verse from which the NIV can claim that the KJV had dropped words. It looks like the NIV added words..