Well, the Cross and Christmas origins are things you will have to research. There is certainly a lot of debate on the subjects!
The Greek word used for the instrument of Jesus execution was Stauros and it usually meant just a pole - while others argue exceptions. As I say - some debate on that.
The main reason we don’t promote it in worship however, is we consider that idolatry.
One thing is for certain - the cross was a religious symbol long before Jesus and didn’t become commonly associated with Christianity until hundreds of years after Jesus death. Sort of the time when Emperor Constantine started promoting Christianity to unify his empire.
Christmas popped up at that time too. It adopted lots of the customs of the Roman festival of Saturnalia which concluded on December 25. That’s where the date came from.
While the Bible is very specific about remembering Jesus death and the exact date of it (Nisan 14) - there is no mention of the date of Jesus birth or any Christians celebrating it.
Constantine was no fool. He knew if he was going to unify his empire under one religion he would have to keep Christians and pagans happy. He was a Sun worshiper himself. That’s related to him making Sun-day the special day of worship.
But don’t take my word on it. Check it out in Encyclopedias.
It’s all quite fascinating when you start digging into it!
Here is the official JW explanation on their website if you like:
I will address your other good questions about “the end of the world” later if you like. Thanks for your thoughts.