With a $400 budget I have limited options for my first dslr, lens, etc. But whatever I choose I do seem to have the option of an older prosumer camera (about 6 years old) or a newer (3+ years old) consumer model. Considering the budget, what would you pick
Neither. Digital photography has changed as much in the past 6 years as other technological areas. Perhaps more. Sensor resolution, low-light ability, autofocus improvements, everything about digital photography has improved by leaps and bounds in the past 6 years. I would not recommend starting with a 6 year old camera.
Likewise I would not recommend starting with a low-end 3 year old consumer grade DSLR. The sensors are not always that good, the low-light capabilities are not always that good, the shutters have limited actuations.
Add to that the fact that for $400 you are going to get a low-quality lens with whatever you purchase. As was mentioned by someone else, my recommendation would be to wait until you have more to put with it. That budget is just not much to work with and you are not going to get something you can grow with, you are going to get something you will be looking to get rid of in 6 months or so.