I don’t think being pardoned absolves one from being subpoenaed to testify, or from having to produce evidence responsive to a subpoena or other discovery. A pardon might also prevent the recipient from taking the fifth. Thus Hillary might not be completely in the clear with a presidential pardon in her pocket, and could conceivably be subject to contempt of Congress or a court if she refused to comply with lawful discovery.
I’m not a lawyer, but I did stay at a Holiday Inn Express last night.
If she gets the nomination next year it is unlikely that this will ever be followed up by legal action no matter who gets the WH,