I'm not much help in terms of the weight and height gain, as my girls only 7 months old.
I might have a few suggestions for the food because my hound/shepherd(?) mix has the same issues. He ended up losing a lot of weight in the shelter then started gaining, but all of a sudden lost quite a bit. Which in terms of weight was fine because he was a bit overweight but his sudden lose of appetite was unsettling. We tried over 5 different brands of food with zero change in appetite after 2 or 3 days of eating it.
What we found that worked was changing him to a high quality food which was stinky and smelly. We chose Orijen for this purpose (averages about $40 a month since he's not very active and is only 60-65 pounds.) But I know there a quite a few high quality (smelly) foods that don't get nearly that expensive.
Then we add pumpkin (he loves the stuff) which works really well for him, he hasn't missed a meal and we're on his 2nd bag. So pretty good for our major picky eater. We previously had tried adding his favorite treat (string cheese) 100% pork and beef and regular canned dog food plus way more. He wasn't interested until we switched to the Orijen and pumpkin combo, now instead of missing meals or walking really slowly to eat he comes up really quickly and eats.
I think the major reason he stopped eating was because of stress. When he was at the shelter he way underweight due to the constant barking and motion (other dogs) at the shelter, he's very much a non vocal (by choice) coach potato so I think it was to much. Then when we got Olivia a few months later (profile pic) he again went off of food.
So it's possible that if your dog is anything like our Murdoc he could be stressed out and just not wanting to eat. Our maybe just changing up there diet to something else that smells could work, seemed to do the trick with Murdoc.
If your dogs lose of appetite bothers you could try to give a beef knuckle or other such meaty treat. That way your dog has at least something in their stomach. However there is that fine line between getting a dog to eat and rewarding them for being picky so that's something you want to gauge.
Picking up Murdoc's food never worked for us, that's why I mentioned this. He would just flat out starve himself and go days without even a nibble. However I know a few dogs that picking up the food trick has worked for, just not ours
Thanks,
Alyssa