According to CRA Attribution rules, what you need to do is determine who contributed to the investment and what percentage. You report the investment income earned in the same proportion as the funds that were contributed to the account that earned the income.
You cannot change the amounts strictly for tax advantages. Generally spouse's claim 50/50.
The same goes for reporting your Rental Income. As a rule, when spouse's jointly own a property, that property is considered to be owned 50/50 and your rental income and expenses is reported the same way.