This is a thought, this is all it is, just a thought - what if we put ourselves in the shoes of someone that has never seen the movie… what if, we keep the suspense going a bit longer, so, you have no mention of Palpatine in the crawl…
A delayed emperor reveal seems to be the original plot line. Your thoughts on how to do it are quite valid and would work. Though the way I handled it is once Palpatine threatens to use his fleet against Kylo he’s like eff off old man— so he retrieves the Wayfinder and heads off to confront Palpatine. If Hal wants to go for a more radical Rey Nobody edit your ideas could work while still keeping the Mustafar intro.