For captions, each label is linked to a single heading style, and the chapter numbering for the caption is obtained from the linked heading style.

If you want your captions to follow a legal heading numbering system then you will have to create a set of caption labels that link a set of caption labels to the relevant heading styles.

E.g.heading

Figure links to Heading 1
Figure2 links to Heading 2
Figure3 Links to Heading 3
Figure4 links to Heading 4

and likewise for equations

equation links to Heading 1
equation2 links to Heading 2
equation3 links to Heading 3
equation4 links to Heading 4

You then need to apply the caption label that reflects the preceding heading style.

Alternatively write a couple of macros that look backwards from the caption insertion point and inserts the relevant equation or figure caption based on the first heading style that is found.

You'll probably also want a macro that can scan through existing text and revise captions based on the preceding heading, just in case after editing the heading level has changed.

You create new labels using

References.Insert Caption.New Label

You link to the appropriate heading level by selecting (from the 'Insert Caption' dialog box)

Numbering
Tick the include numbering box
Use the pull down menu to select the heading style that will provide the chapter numbering for your figure/equation caption label.