It will slightly go down I think. The recent price rally and stability in $5500 range may be caused by people who bought BTC in order to get free BCG fork coin. After holding those BTC, people may dump it back and causing a slight downward movement.
Answer to 2nd question, yes. I personally think that holding BTC is always a good move for the long term. I've proved that so far. So, hold those BTC and sell BTG for free BTC as soon as possible

Totally agree with you opinion. The pricing of Bitcoin after October 25 will be decrease but not to the point lower than $5000. It would normalize to $5400-5700 and will climb eventually.