First off, Leman Russes can't take Daemonic Possession or Oh boy, you guys would be screwed.
Secondly, here goes-
Traitor Guard is not Lost and the Damned. The Servants of Slaughter, Servants of Decay and Renegade Militia lists from FW are not lost and the damned. It comes pretty close in some ways but at the end of the day, they are neutered thematic lists which lose some things in 5th edition and were based off the old 3rd ed Imperial Guard codex. Yeah, I roll these lists in friendly games. They are outdated, hardly functioning where certain tweaks tend to be applied so they aren't rail roaded.
Since the IA5 lists mentioned above used the 3rd ed imperial guard codex as a guide, one could assume that using the new imperial guard codex to represent renegade guard would be a logical jump.
Renegade Guard are a staple in 40k. Remember, there was only 1 Vraks to produce a Vraksian Apostate Preacher to bring about a Vraksian Rebellion filled with Vraksian Renegade Militiamen which was later annihilated. (Represented in an almost scenario like way in the Servants of Slaughter, Servants of Decay and Renegade Militia lists)
There are hundreds of worlds where guard turn renegade, take their equipment and follow chaos. Since the removal of the Eye of Terror codex and the lists contained, there have been many players, myself included, who have been looking for a way to better represent a band of ordinary men that worship chaos. Millions of men turn from the Imperium and join Chaos or some permutation of it. The great story and theme behind chaos is that it is everywhere, not just in huge bloodthirsters or 10,000 year old Chaos Lords but in men. Lunatics that join chaos because they were left outside the light of the Imperium too long. I could go on but then it would get even nerdier and deeper into my fluff dungeons.
Do I think traitor guard should be allowed? Yes. Should there be limitations? Yes. The limitations should be as follows: Modelling and Special Characters.
Since Apocalypse allows for using multiple codecies, there is no reason to worry about having a close combat monster as your HQ as the Daemon Prince/Chaos Lord / Some jerk with an 8 pointed star on his head has come for his flock. A requirement of some chaos HQ must be taken.
Modelling: It must be chaos. It comes in all flavors and views and that's what is great about chaos. My renegade guard are modeled to be ramshackle followers of chaos with little adornment save for a few hastily inscribed chaos markings and crude paint on starts on the vehicles. Some take it further and more Lost and the Damned like puts spikes on everything. Those would be opposite stylistically but convey the same idea. The army must look like it has fallen to chaos and have it be obvious.
Special Characters: I would remove the ability to remove the ability to take some some of the characters like say Creed. He stopped the rebellion on Cadia where a horde of Imperial Guardsmen went Chaos. Obviously out. I'm not too familiar with the other characters except for Pask (
) and well you can read through and see if any could be represented in a chaotic way but to keep it simple, you could lean toward just not allowing them for renegade guard.
Renegade Space Wolves...
You have to take Huron and have to use the CSM codex to represent the army. The CSM codex can do much of what the Wolf codex can do and it keeps things from going weird. You could use your models, just not the codex.
This ultimately depends on the ambiguity of the paint job. Huron Blackheart was / is a pirate. He runs around raiding while forcing people to join his cause or killing them. Space Wolves joined him because they did not want to die. Thus breaking their resolve and knowing fear.
Renegade Space Marines...
The new Chaos Space Marines book is just that- Renegade Space Marines. With the removal of the cult rules and ancient enemies and other theme base rules removed, it is implied to be played with a certain type of all inclusive chaos where all 4 cult squad types could be in the same army. So it covers the play styles of lots of people but keeps things on the Chaos rules set. Have lots of drop pods but a pretty ambiguous paint job? Counts as Dreadclaws and play as undivided chaos. Big gold proudly displayed aquilas need not apply.
Oh and remember- As per the Apocalypse rule book, Chaos has access to all Imperial Datasheets. Some can be represented properly as they are single and self contained models like the Titans, fliers, etc. but others can only be made up of Imperial only selections. An example of this would be the Assault Force of the Ancients would be impossible for Chaos to take since it contains a tech priest.
TL;DR
The imperial armor renegade lists are outdated and barely functional as a stand alone list
Space Marine players should don spikes if they want to hang with the spikey marines
Creed does not work for Chaos, yo.