The sacrifices were never a part of the original law. "They were added because of transgressions (Galatians 3:19) until the Seed to whom the promise referred had come." This sacrificial law constantly reminded Israel of their failure to live up to the terms of the Covenant. It involved laborious sacrifices and ritualistic washings, rites and ceremonies.
The Holy Days did not originate with Leviticus. The Levitical system did not begin to function until one year after Israel had left Egypt. The Holy Days were instituted when Israel left Egypt(Exodus 23:14)......conversely, the abolition of the sacrificial system did not abolish the Holy Days, (Hebrews 9:10 "They are only a matter of food and drink and various ceremonial washings-external regulations applying until the time of the new order."
I Corinthians 11:1 Paul says, "Follow my example, as I follow the example of Christ". Jesus observed all of the Feasts and Paul observed all of the Feasts. The New Testament Church of God observed all of the Feasts. We will observe the Feasts in the next age (Zechariah 14:16-19.
You are plainly incorrect. The "holy days" were added in the same context as the sacrifices. There is no biblical reason to divide the cultic law that was given to Israel through Moses over a relatively short period of time. It's an arbitrary decision on your part in order to make some theological point.
The fact remains that the "holy days" were part and parcel with the Levitical system. E.g., the are given their fullest expression in the book of Leviticus. Any attempt to bring them into the new covenant, even in an expurgated form, is a denial of the finish work of Jesus Christ on the cross.