Hi ggggt, yes, the 4-star cards which is in the first gold chest has a higher rate to drop in the previous map as well as the current one. The chess dragons are not going to be reclassified as dragon type cards as changing them may result in many owners changing their team formation.
Hi browncoat, if you set the randomness aside and only look at the drop rate, it is easier for you to get two 4-star Earth Less Demoness in the hell stage than one 5-star Earth Demoness in the insane stage.