one last query regarding amount I can claim on line 303 for my spouse. Will this amount be also be prorated?

Yes, it will have the same treatment.

Hi, below site mentions that foreign income only includes foreign shares, rental properties or business income from outside of the country. Does employment income is also considered here??

https://turbotax.intuit.ca/tips/do-you-need-to-declare-income-earned-from-sources-beyond-canada-6227

Any and all income.  Total worldwide income.