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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Some 26 schoolchildren who went missing in the Brecon Beacons during a Duke of Edinburgh exercise have all been found safe and well.
Charaf Elmoudden went to the singer's four-bedroom house in north-west London last year and made off with goods worth more than £200,000.
The plea has been postponed in case where man is accused of dismembering a police officer he met on gay dating website Grindr.