Is there any pressure on them to release this information? Or the figures in involved?
Lloyd Evans (and probably that exJW group too) called for a separate investigation into the JWs and asked the Inquiry to request files from the branch (a recent example) but it's unclear whether the panel is willing to do this.
Will the Kingdom Hall Trust, IBSA, and Watch Tower Britain be liable?
There are various possible scenarios, but in most cases it will be possible to sue, depending on circumstances, WTB or KHT.
Has Gillies ever explained whether long-standing elders have been questioned or checked for past involvement in child sexual abuse?
No, afaik
It seems to me that the Circuit Overseer and the elders in each congregation are responsible for appointments of elders and ministerial servants and so the body corporate cannot be held liable for compensation.
Why? Elders act under supervision and control of CCJW/WTB, policies are established and disseminated by CCJW/WTB, circuit overseers are appointed and paid by CCJW/WTB, congregations are officially declared KHT branches etc. etc.