When will this Xmas pack be released and what kind of cost are we talking?
No information has been revealed yet.
Back when this was originally released (Dec '16) 0.1 BTC was like $75. Can the cost of the licence not keep up to date with the value of BTC?
It
did keep up the price (albeit some things got cheaper, e.g. 2nd licence). It was 0.1 BTC then, and it is 0.1 BTC now. We should be pricing things in BTC, and not in USD.