There have been no changes to the Law so claimants can only receive ESA(IR) when they are entitled to it, so yes, the DWP need to assess the period from today back to when the claimant was transferred from IB to ESA.
I'm not sure there is a definitive definition of an asset but in broad terms, it includes property, other than the one that the claimant is living in, financial products such as an ISA or Premium Bonds, disposable items such as gold but not usually jewellery and other "personal" items. Anything that might reasonably be labelled as an investment.
Gordon
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