Once you unpack the BSA and strategy poking around and opening textures in an editor, you'll see what I mean. You'll probably end up replacing most of those textures at some point but the are some textures from the Hi-Res DLC, like the Hall Murals, that fill a need.
I want to clarify. There's making a Merged Patch and there's using the merge script to combine two or more .esp files. The merge patch is like a Bashed Patch for records that aren't a Leveled List. It's good for carrying records forward that otherwise aren't carried forward. The downside is that it requires manual tweaking that can be time consuming. (At least it is in my game.) So, if you add new mods, you have to check the Merged Patch, adjust, or re-create.
It's easy to miss things is TES5Edit. Along my modding journey, after I've added new mods, I've experienced CTDs, had to open TES5Edit and make adjustments. This is even after I've opened the mod upon install. I run TES5Edit and alt-click every new .esp. I miss things all the time because as I mod, everything is always changing. Particularly if I'm adjusting my load order along the way. Hey, it happens.
Since it's a new save, it's either a mod, your load order, or something is causing a needed record to be overridden. (Assuming that you are already using the SKSE memory patch.)
Also, IIRC, there's an issue with HF and the SDO Morthal plugin. I can't remember if it's an instant CTD or holes in the landscape. (I don't use the SDO optional plugins, just the meshes.) The SDO page will have the details.
Yeah. The quests are wonderful too. They blend in with the vanilla game and add up to be nice little surprises. The quests are neither too long nor too short. I wish he was still making mods. The one thing you will probably encounter are epically distracting shadow artifacts in the two plugins I mentioned. Fortunately, they are easy to fix by increasing the value for Shadow Depth Bias on the lights that cast shadows.
Also, Laintar Dale and Oakwood make HF for me. There's also another mod that creates a row boat at the Solitude docks that travels to your home at Heljarchen Hall, similar to the Solitude-Dawnstar-Windhelm boat. Combined with Storefront, these mods really enhance the overall HF experience.