Racks and Bars are interchangeable, so don't be afraid to mix and match. I believe both of the above racks come with locks and will serve you well. Decide what will work best for you and find it at the best price as recommended above.
Yakima bars are round, thule are square. The fittings are shaped to fit each brand so you kinda do need to choose a brand and stick to it unless you wanna pay extra for adapters n shit