So here's what I know you can do (name followed by the quest you should start but not complete):
People
Animals
Summons
- Two summons (with 100 in Conjuration and the Twin Souls perk). Some dead thralls can summon atronaches, so that gives your summons one summon apiece.
which brings the total to you, nine people, two dogs, a horse, two dead thralls and four atronaches. That's 13 permanent and almost everywhere (excluding atronaches and the horse) and 18 potential. This seems pretty hypothetical and I haven't done it myself, so feel free to correct me.
Other
There's also supposedly a glitch (patch status unknown) where you can dismiss your follower, hire someone else, then immediately return to your follower and rehire him or her. I don't know if people use it with the Dark Brotherhood Initiate(s) for a reason or because it only works with them.
Also Odahviing.
How to fix (2013 update)
I've tried the bugged saved game file I initially posted in my question with the current latest versions of the official patch, Unofficial Skyrim Patch (USKP) and Skyrim Script Extender (SKSE), and the saved game is now Aspect of Peryite-free.
I've configured SKSE to use its ClearInvalidRegistrations
console command on every saved game load, which removes invalid scripts left running by uninstalled mods. This feature was introduced in v1.6.7 of SKSE:
add console command ClearInvalidRegistrations
to remove invalid
OnUpdate() registrations
This prevents orphaned OnUpdate() events and
the resulting bloated/broken saves when removing certain mods. When
applied to an already bloated save, it will stop growing further and
instead shrink over time as the game processes all queued events. This
may take hours depending on the amount of bloat.
To execute automatically after each reload, add this to \Data\SKSE\skse.ini
:
[General]
ClearInvalidRegistrations=1
According* to a developer of the Unofficial Skyrim Patch (USKP), the underlying cause is because DA13 ('The Only Cure' quest) is never stopped.
A possible fix* for this:
In the meantime, load an affected save, then type stopquest DA13
into the console. That ought to put an end to that. Plus it’ll free up some unnecessarily leftover alias memory.
BTW, don’t use the console command on a save not bothered by it. Even though it may appear benign, console commands can have negative consequences you don’t know about.
If this doesn't work or if you experience issues like: NPCs not responding properly to conversation (not reply to you when you choose a certain conversation path - leaving you stuck), merchants not opening the buy/sell window, horses that can't be ridden, and other interaction issues, then the save game is most likely corrupted. Try the SKSE ClearInvalidRegistrations
console command fix I've posted above, instead.
To prevent this from happening in the PC, get the latest version of the Unofficial Skyrim Patch. This has been fixed since version 1.1 of the USKP:
"The Only Cure" (DA13) was never stopped which would lead to the Aspect of Peryite randomly initiating conversation and being unable to exit.
* This info is from the old USKP bug tracker page at 16bugs.com, which is now not viewable. The new USKP bug tracker report page of this bug is at afkmods.iguanadons.net.
Best Answer
The full list of trainers capable of serving as merchants is as follows:
Base Game
Dawnguard
Dawnguard adds three new trainers who are also merchants.
Dragonborn
Dragonborn adds three new trainers who are also merchants.
Now, this all may be a very large list, but it's unfortunately not a very promising one. The best choices for selling goods to are generally Fences, as they have the most money (depending on your Thieves Guild side job completion), and also buy anything without need for the Merchant Perk. But the only Fence who is a Trainer is Ma'jhad, who is part of a Khajiit caravan; if you find yourself needing to wait around for his gold to replenish at any point, he will likely be in a different city when you're done.
Your next best bet is probably going to be a blacksmith, as several of them have a thousand gold (including all three who are also trainers), and they buy many of the items you're looting off enemies, even without the Merchant Perk.