Instead of solving each problem separately and changing the way you guys have set up the app (because I can see why people would like to have budgets or categories or overviews in different wallets), why don't you give us the ability to select wallets that we want affected by the change.
For example, I go to budgets and I add a budget, I put the budget in, select the category, and then tick off the wallets that share this particular budget. Would this work? That way certain budgets or categories or overviews could span some wallets and not others, or just one, or across everything.
So with that in mind maybe a poll for you guys? CBO = categories, budgets, and Overviews