Regarding Palpatine. I felt like putting in any indication of another threat would ruin TLJ’s hopeful ending, but I’m hoping the following suggestion would lean into ESB-levels of hopeful ending despite the Empire still existing, and not “Why be hopeful if another threat exists outside of the FO, even after the actual FO loses?”

When Rey and Kylo arrive at the throne room, have Snoke be in the middle of contacting a man attached to a machine: “Everything is proceeding as you wished, my master.” A familiar, booming voice praises him through the device: “Good.” Snoke shuts the hologram off and turns his focus to Kylo Ren and Rey.

(I’m hoping that by killing Snoke, in this… suggestion, Palpatine would be “severed” from the FO so the hopeful ending would be preserved… until TROS.)