First off I am sorry to only be around every now and then these days.
Now for my take on this - based on a large amount of posts read and some info from private parties involved in testing this and customers creating hybrid dolls( I do head-body adapters).
Whether or not TPE and Silicone react depends on the actual two substances in contact, i.e. the precise type of TPE and the type of silicone.
The thing to look out for is oilyness developing at the contact area( fact) and as far as is known it is most likely not a direct chemical reaction but more likely an indirect one where the substances do not "react" as such( forming a new substance) but where one substance kinda invites to store the other better, resulting in the Silicone to get brittle( it is leaking silicone oil) and the TPE to get mushy( it incorporates the oil into its cavities instead of the mineral oil normally there)( attempted explanation, may be wrong).
The extend to which this happens has been reported as bad as significant oiling within minutes and severe damages over long exposure time( see Haremlovers Z-One) on one end and I also know about combinations that apparently do not have any issues even when in contact for hours - mainly with 4woods Silicone involved.
So the verdict is to err on the save side and keep the two separated as best you can and to at least initially have a keen eye and check often if you are actually having a setup where contact may exist - be it a photo session or a hybrid doll.
Thankfully, these issues seem to be related to RTV-2 silicone only, certainly so for the platinum cured ones and possibly also for tin cured ones but do not happen( to the best of my knowledge) with RTV-1 silicone( humidity cured) such as Silpoxy, Permatex Flowable Windshield sealer or Wacker E43 / E4.
Tests indicate that RTV-1 will show no "reaction" at all with TPE( again, current knowledge of limited TPE probes) and since its used to glue RTV-2 or paint on it is also safe there.
That makes RTV-1 the currently best "separation washer" for hybrid dolls( TPE head on Sil body or the other way round), the only known issue being that the RTV-1 will not "stick" permanently to the TPE side so if you apply it on that side you will have to check everything is still ok every now and then.
I hope this helps a bit.
Kind regards.