Ehhhh canned food is expensive and puppies can become accustomed to having it and refuse to eat without it. With an older dog who's not eating or needs to gain weight maybe but I wouldn't recommend it with a puppy unless you are prepared to have to always do so. Honestly we also got our EM at 7 weeks and she was 11 lbs. She was just a little girl. She gained slowly at first and is now gaining a little more. She turned 15 weeks today and is 35 lbs. The problem with mastiffs is you don't want them to grow too fast which a lot of foods that are too high in protein can cause. I know it's hard because you see this itty bitty puppy and you know they are supposed to be a big as adults but if he's eating well and has been dewormed, I say just give it time. Puppy Chow is awful so I'm glad you've acknowledged the need for change. If your vet expresses concern or you really don't feel he's growing adequately you can try satin balls as well. Here's an example of a recipe
http://www.holisticdog.org/Nutrition/Satinballs/satinballs.html . I believe there are several people on here that use/have used satin balls and might have recipes they like better. Just remember the key is slow and steady growth. As far as the crate, we crate train but not at night. Our dogs sleep in our room/bed from day one and we do the crate training during the day, starting with 15 min at first and then going up to about an hour. Mind you we are home during this so we can tell if the dog is having a really hard time or if they are just being dramatic. Some people like to crate train at night though so everyone's different. Just like everyone has a different opinion on food. My opinions/belief come from literally hours of research and a dog nutritionist who was kind enough to educate me/point me in the right direction. At the end of the day, your dog is your dog so do what works for you and your family. Hope you find something that works for your pup!
---------- Post added at 12:52 PM ---------- Previous post was at 12:45 PM ----------
Thank You Cody! Smart Family I was happy to see I wasn't totally off base when I changed our foster to Natural Balance because that is on your list. However I did notice that I missed a very important point when I used to purchase it for him(we no longer have him) was that I was buying the Large Breed bites that were all natural and since Mastiffs are considered a giant breed maybe that isn't the brand to go with. I do remember checking the calcium balance on the food and it being a higher than most "large breed" foods? So many choices hahaha!
That list of food is a good list to start off with, however not all those foods are good for giant breeds. In all honesty most of the time you buy any kind of formula that is specific i.e. large breed, puppy, small breed, senior, etc. you are usually paying more for the same thing that is in either the adult formula or an all life stages food. Also people use to think that higher protein levels are really what causes growth problems in larger dogs and while this is partly true it's more that foods with a higher protein level tend to have a higher calcium to phosphorus ratio which is what can cause the most problems. Some foods that are great like Evo and certain formulas of Orijen and Acana have protein levels too high for puppies but are good for dogs over the age of 18 months or so. In general you want a calcium percentage under 1.8% but ideally closer to the 1.4 to 1.6 % range.
We adore our new little man and he already is doing a great job at going potty outside as long as his mommy or brothers and sisters are paying attention close enough 
He was born Nov10 and is brand new to our family so we haven't gotten him to the vet yet, though he will be going soon, I would love some advice on what and how much to feed him. I weighed him on my scale and he ways around 11lbs. We are trying to be strong about making him crate but he really is a much better sleeper with us...I know I have to stop it... but right now he is so little....and he was first pick of the littler and I think he is lonesome 
