get commerce order variables dpm without loading order again
You need to use commerce_order_load to load the order with all the data. If the order already has been loaded somewhere else on the page, the order won't be loaded twice, but the order will be fetched from static cache instead. So it's fine to load the same order multiple times.

If you do need to clear the cache, (maybe you need to compare the order to what is in the datebase to see what has changed), then you can use use commerce_order_load_multiple or call entity_load directly.