I'm not sure how to tell u since I fed mine with barf when she still a pup.
One thing for sure, for puppy they need to eat more about 3 to 4 times a day because they're still growing. Yes, you can soak the kibbles with water before feeding but... 20 small pcs? I guess that is too little for them!! I'm not sure how many u should feed but definitely not 20 small pieces unless you want to control their size like some ppl did, then you can control the food either.

My advice for the food, u can refer to the kibbles package as they will stated there how much a puppy should eat. Thou different scoop that u refer to will also affect on how much you should give

In any case... please let your boy introduce himself here 

If you can feel their ribs easily, it means they are not eating enough so you should feed more.... No offence but your seller (i personally wont call these type as breeders) probably misled u to ration your puppy's food to stunt its growth so that they can prove that its a so called mini maltese...

Its not true. Angel shave once before due to a lot of tangles, end up her fur is not as straight as before. But her puppies fur all very straight without even need to straighten the hair.

It might true if you're talking about poodle breed but in my experience never ever SHAVE bald a maltese coat! Due to some accident 1 of my malt got shaved and her new coat is not straight as before. In fact, after shaved her coat became so curly and a bit rough.... then few months back I shaved her again due to skin problem (which I don't want to shave at first but since the coat is getting...... due to the 1st incident I decided to shave it again to see if there's any different from the previous shaved) and I start giving her skin and coat supplement to see if I can save her coat. Now the new coat is not as rough as before but still very curly. So my advice is, if you want to cut it short just cut it short enough as puppy cut but don't shaved it bald.

I'm not sure why but I did heard some groomers are telling their customer to shave bald the dog either poodle or maltese owner and I found it funny when I listened to them. Reason being, I had this groomers which I often went to ever since I got autumn and the owner never ask me to shave the coat. She even asked me twice to make sure I'm not going to regret cutting the coat short when my malt was having long coat last time. She always objected when I want to shave bald my maltese when I thought the idea of new growing coat might be better than the current 1 and I really appreciate her thou I did shaved my malt but due to skin prob. If not I wont shave her at all