Can disbursement function code 2190 also be used for SPED-related costs?

No.  Disbursement Function 2190 is only used for non-SPED student services that are not classified elsewhere in the 2100 series.  If SPED costs are accidentally coded into 2190, they will not be included in your SPED reimbursement through the  SPED Final FInancial Report.