A Mediterranean couple sought in connection with Williams' death is now considered a "red herring" after further police inquiries.
Organisers of the ladies fashion course Williams' enrolled on in secret will give statements to the inquest too.
The lawyer for MI6 says calling corporate witnesses will "paint a picture and set the scene".
Two experts have tried to reconstruct how Mr Williams could have got into the bag and locked it - The coroner says he wants a live demonstration in court.
The issue of whether or not Mr Williams could have got into the bag and padlocked it from the inside "goes to heart" of inquest the coroner says.
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Patrols including local volunteers have been set up after the grisly finds in Thamesmead in the last month.
Thieves targeted a property in Richmond on Monday afternoon.
The station, which saw 44m people commuters use it in 2016/2017, will be transformed into a dining room complete with Christmas decorations.