Hello Truth7t7, you believe that pagans "own" a date on our Calendar
While that is clearly not true, of course, I can imagine that it might be true in the minds of certain individuals. And if that's actually the case (and it may well be), then the very last thing we would want to do is to intentionally/openly avoid doing something of a special nature on those days as Christians, because doing so would lend a certain credence to their thinking, that it might actually be true (and could, thereby, be instrumental in leading them both deeper into their deceptions and further away from the truth).
So, taking back ownership of October 31st (from those who associate it in their minds with a pagan holiday) by celebrating that day (the day that Martin Luther nailed his 95 theses to the door of the Castle Church in Wittenberg) as the beginning of the Reformation of the church instead, seems not only a good thing, but the right thing to do (especially for the sake of those who hold it to be a "pagan" holiday).
As for Christmas being celebrated as a means of replacing the Winter Solstice, Christmas is always on December 25th, the Winter Solstice never is/never will be on December 25th (it happens on December 20-23) so that doesn't seem like it should be a problem .. unless we are going to start eliminating more of our calendar days because they fall ~close~ to pagan holidays I see no reason to do that, of course (and remember, close only counts in horseshoes and hand grenades ).
That said, I ~LOVE~ the fact the Christmas is a worldwide, annual celebration of the Lord's birth (even if it is barely recognized as such by some, it is still a fact that is known to all who celebrate it). It is certainly a day that avails itself like no other for proclaiming the truth about our Savior's coming to a world that so desperately needs to hear the truth about Him
Finally, while many things are spelled out for us in the Bible as sinful (both directly and indirectly), I do not believe that our choice to celebrate the Lord's birth, or His death and Resurrection, and/or things like the Reformation of the church, are numbered among them!
In fact, the Bible has this to say about a very important day in the lives of the saints,
Psalm 118
24 This is the day which the LORD has made;
Let us rejoice and be glad in it.
Granted, few, if any other days could be considered as important as the "day" that this verse, Psalm 118:24, ultimately points to, which is the day that our salvation was made a reality by the Lord on the Cross, and then by His Resurrection three days later.
So the celebration of such days seem quite Biblical (remember too the celebrations that happened on the day of the Lord's birth, and on the days following it as well, by the angels, the shepherds and others like the wise men from the east).
God bless you!
~Deut
Luke 2
8 There were in the same country shepherds abiding in the field, keeping watch over their flock by night.
9 And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid.
10 And the angel said unto them, Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people.
11 For unto you is born this day in the city of David a Saviour, which is Christ the Lord.
12 And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger.
13 And suddenly there was with the angel a multitude of the heavenly host praising God, and saying,
........14 Glory to God in the highest,
........And on earth peace,
.......Good will toward men.
15 And it came to pass, as the angels were gone away from them into heaven, the shepherds said one to another, Let us now go even unto Beth-lehem, and see this thing which is come to pass, which the Lord hath made known unto us.
16 And they came with haste, and found Mary, and Joseph, and the babe lying in a manger.
17 And when they had seen it, they made known abroad the saying which was told them concerning this child.
18 And all they that heard it wondered at those things which were told them by the shepherds.
19 But Mary kept all these things, and pondered them in her heart.
20 And the shepherds returned, glorifying and praising God for all the things that they had heard and seen, as it was told unto them.