I did some more investigation, and it seems the solution was far simpler than I was imagining. I was able to update the Actuals, Expense formula in K22 and the Actuals, Income formula in K23 to sum the Modified Actuals in AO11:AO rather than the Period Actuals in AI11:AI. Making this change yielded the expected expense and income values in the sparkline.
Actuals, Expense, K22
=sumproduct(($AE$11:$AE="Expense"),($AG$11:$AG<>"Hide"),$AO$11:$AO)
Actuals, Income, K23
=sumproduct(($AE$11:$AE="Income"),($AG$11:$AG<>"Hide"),$AO$11:$AO)
On a side note, I do not recommend adjusting the formulas for Actuals Prior to Period in P10 and Actuals in Period in S10, as it throws off the ACTUAL calculation in E12, and possibly elsewhere.
I also noticed a polarity issue for Net Budgets in K13 for all periods. The formula is set to Budget, Expense - Budget, Income whereas the current period calculates it in K21 as Budget, Income - Budget, Expense. I made a simple correction of swapping the terms.
Net Budgets, K13
=K12-K11