My read on that is they allow the withdrawal on the other blockchain in but would then burn what exists in equivalent amount on the ETH blockchain and that keeps the equity value overall equal between the two. Rather then duplicating which could be the same as dilution of value. GAS fees might drop in forthcoming changes, they altered the bid system for GAS recently I wasnt following it too closely but they are burning ETH there also with the idea fees will become less variable plus the whole POS thing.
Lambo lottery isn't a big loss for FBC because there were 2.89 mln golden tickets in the previous round of this lottery. Correct me if I'm wrong, but it means that FBC got ~720 BTC for these tickets due to house edge.
It wont be a fixed amount because some are bought or gained and also house edge isnt exactly fixed now with FUN token also varying it. So long as it raises revenue and its cheaper then advertising then its within the website model I think. I reckon quite a large amount of people get a golden ticket almost every day from gambling or more if really betting with size, since it covers both chance and the sports events etc. thats a definite prospect for alot of bettors.