Given the constraints of OP’s original post, this is probably as close as you can get: make sure the feature phone you choose already comes with a navigation app that supports your needs, because there’s no realistic way to add one worth using.
I recall seeing the spec list for OP’s selected feature phone that its hardware includes GPS, so odds are good it comes with some kind of mapping/nav app. Hopefully, it scratches OP’s itch.
Take a look at Republic Wireless. You have to buy a Moto phone from them. Plans cost as little as $5 a month.
Two gimmicks:
All support is online, no live customer service by phone.
Their phones are designed to use WiFi first and to use cell towers only if WiFi is not available. If you are in a WiFi-dense city this may work well for you.
Ting also has very cheap plans. You can buy a phone from them or use your own Sprint phone. They have live real English speaking support if that is important to you.