i think that critical care & essentials for life are meal replacers. i know the efl has some herbal benefits. i love all the oxbow products but my chins just would NOT eat the CC, especially the anise flavor. i was able to force some of the apple banana but had to add stuff to it. its not a bad product, i just prefer the essential for life. i like the way it smells, my chins like it, and i really like tanya's products.
as for the lifeline. i love love love that product. it is a product made up of a lot of different herbs and other ingredients to help chins with several issues. while it probably could be used as a meal replacement, it is a bit rich and much more expensive per ounce.
personally i would use crushed up pellets, canned pumpkin and lifeline mix until the essentials for life arrived. than i would exclusively feed the EFL until your chin got their weight up and i would start mixing the crushed pellet to hopefully encourage your chin to eat pellets when all this passes. just my opinion. i am not an expert, but i have watched one of my boys goes thru a lot of teeth issues and digestive issues until i got it right.