For some unknown reason, when inside the WInking Skeever in Solitude after I parted ways with him, he suddenly started shouting and attacking another NPC. I used console commands to add an npc, Talsgar the Wanderer, as a follower.
SKYRIM SPECIAL EDITION ETHEREAL ELVEN OVERHAUL MOD
This mod has open permissions with these licensing terms: "If you use any part of this mod in your work, you must release it under Attribution 4.0 International (CC BY 4.0)" which may be incompatible with STEP terms. The changes are so tiny that they could all be included in the CR patch and this plugin could be omitted entirely. There are conflicts with Atlas Map Markers which always wins, and other mods depending on where LOOT sorts this plugin. Both mods can be used at the same time, load order doesn't matter. Note: this mod also includes the sunlight trick for Shalidor's Maze, so it's partially redundant with 'Labyrinthian Shalidor's Maze Fixes', but not completely, as it doesn't contain the latter's other fixes. Unfortunately the big statue (in the center, not visible on screenshot, behind the rocks with the giant) doesn't appear to cast shadows. Giant's Grove (Serana decided to appear out of nowhere and follow) STEP base (no Weather & Lighting mods) > STEP base + DVLaSS + Shadows of Sunlight This mod applies the same trick used for allowing the sunlight to shine through another two small areas, as with Labyrinthian Shalidor's Maze Fixes: Giant's Grove, and Castle Volkihar Courtyard.
Shadows Of Sunlight - In Small Exterior World Spaces by wSkeever