Suggestion resolved problem, summary:
Forced within ProConnect a digital Form 8332 (unsigned) in the return (PDF signed 8332 attachment linked to form 8332 was not enough to clear the critical error).  Note: ProConnect digital Form 8332 required input of custodial parent's name, which ironically is not on the IRS Form 8332 that is signed by the custodial parent (8332 required inputs of the custodial parent name, ssn, dependent's name and date signed).  I had previously also tried mapping 8332 to Form 8453 with check box [X] on 8332 as being attached, however this did not cure the ProConnect critical error.