Can I substitute dehydrated veggies for freeze dried in recipes?
I think the issue here is long term storage.  If you are only going to keep the food for weeks to a couple of months, I think your home dehydrated products should be perfectly acceptable.

Depending on your application&mdash;and I make no value judgements here&mdash;if you need to store the food for considerably longer for whatever reason, then you want to be sure nearly all of the water has been removed, and commercially freeze-dried products are going to be more reliable.

Also, according to wikipedia:


  Freeze-dried products can be rehydrated [sic] (reconstituted) much more
  quickly and easily because the process leaves microscopic pores. The
  pores are created by the ice crystals that sublimate, leaving gaps or
  pores in their place.


For another perspective, the vendor Rainy Day Foods says:


  When comparing freeze dried foods to dehydrated foods, there are
  advantages to both. Some advantages of freeze dried foods are that
  they are light in weight and reconstitute quickly and will have the
  appearance of fresh foods when reconstituted. A disadvantage to freeze
  dried foods is that they will take up more space for storage because
  they are lighter and more space is needed to store the same amount (in
  weight) as dehydrated foods. Advantages to dehydrated foods are less
  space is needed to store a large amount of food and it is economical
  to purchase. Freeze dried foods can be a great deal more expensive
  than dehydrated foods.
  
  So in answer to the ongoing question of whether freeze dried foods or
  dehydrated foods are better – only the consumer can determine which is
  best depending on his or her own personal needs and preferences.


However, they are addressing commercially dehydrated or freeze-dried products, not home prepared products.

Your home dehydrated foods will probably retain more moisture and have less even quality control than commercial processes.  For this reason, they may not be as shelf stable.

For most uses, though, especially if you are making "meals in a jar" for convenience or short term emergency preparedness, not long term (years) of storage, your home dehydrated fruits and vegetables should be just fine.