The expired dehydrated foods should be safe, if not enjoyable, for consumption. The only reason they would be dangerous is if they were punctured or contaminated during manufacturing. There are tons of Youtube videos of people eating long-expired MRE's from 30+ years ago.
I've approached dehydrated pre-packaged foods from the opposite direction as most backpackers. I refused to eat any when I started because of the nasty taste and bulk/expense, but now I really enjoy them. The trick was finding the best brands and then adding fresh or additional ingredients. I add tahini and a "
sazon" spice packet to Peak Refuel's
Three Bean Chili Mac, dried cranberries and cashews to
Kapka's instant upma cups, just tahini to Peak Refuel's
Butternut Dal Bhat and Heather's Choice
African Peanut Stew, and peanut butter and "Hot Texas Trash" snack mix to chili ramen.
LiteHouse makes excellent freeze dried spices that are 80% as good as fresh, and
True Lemon/Lime packets add a nice acidic kick. Nothing has a better calories-to-weight ratio than tahini and nuts, and I repackage or let the air out of bulky meals before packing.
OldBill may have specific health problems, but most people and even most hypertensives aren't at increased risk of cardio events from eating salt. I've experience hyponatremia at least twice on trips and my body needed more salt so badly that I couldn't even taste it when I dumped two electrolyte packets into my water. Keep in mind we're losing way more salt than we do in normal life, so most of us without sensitivities could probably eat 2x the RDA and be fine. As for dinners with 30-60% fiber, the rest of my backpacking food during the day has almost no fiber so it evens out. I also sleep alone.