I don't know what the pardons cover, but, in general, this means that if Manafort or others are called to testify at some other trial -- perhaps one involving Trump -- they cannot invoke the 5th Amendment or refuse to testify. That would mean that they would either testify against Trump or be held in contempt or, more likely, perjure themselves. Those are NEW crimes that are probably not covered by any pardon.  
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I am expecting that Trump WILL pardon his family, including Melania (for the inaugural party scam and any complicity in emoluments violations funneling inauguration money to Trump properties and friends). I'd then like to see Junior, Ivanka, and Eric squirm during their testimony.  
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And I'll repeat my earlier comment about Trump issuing a pardon to Hillary Clinton for the sole purpose of embarrassing her and making it seem like she was guilty of something. "And I am pardoning that lyin' skank Hillary Clinton, a horrible person, of all of the terrible crimes that she committed against this country, too many for me to list here, but everyone knows what she did, everyone knows. ..."

aggressively pursue Trump investigations. Biden only has four years to make an imprint as a US President, and the more time he spends on Trump matters, the longer he will be seen historically as acting in Trump’s shadow.