The limited supply of BTC should cause deflation of the currency. In other words the BTC will become more valuable as demand continues to exceed supply. This is opposed to how most traditional currencies work. I will use USD as I am more familiar with it. The US Treasury can print additional money. This money is more or less created from nothing. As supply increases and we assume constant demand the value decreases.
As far as divisibility, https://en.bitcoin.it/wiki/FAQ#How_divisible_are_bitcoins.3F
This is a good start. Currently BTC is divisible down to 8 decimal places. If needed this can be increased.
Lower limits will likely be adjusted and fees will be reduced to reflect the increased value of the BTC. However it will take time for companies to adjust their fees. The market reacts quickly, companies will soon follow.
I am fairly new as well so I will refrain from commenting on your last two questions