Hi Inna,
Fussy, gassy, sleepless all describes symptoms of the allergy so it sounds very much like this is what is bothering your ds.
To answer your questions...
1. Yes, the blood was on and off.
2. LOL on the sleeping prior to eliminating milk- she was up, no joke, until 4:30am every night crying and screaming. Then she'd literally pass out from exhaustion until 8ish. In the day she slept heavy but in short spurts. Keep in mind this was from birth until 7ish weeks.
3. Her entire naps and sleeps improved once I eliminated the milk. Now, your lo is older in comparison to when my dd was diagnosed so you maybe facing the 45 minute nap monsters anyways but I do think it's all related.
4. I can't remember the smell of her dirty diapers it was long ago and now I'm used to the smell of the diapers from eating solids

.
5. Milk allergy IS the milk protein allergy. Intolerance is lactose intolerance. Some that are lactose intolerant can handle some forms of milk products whereas allergy- you can't handle any. With the intolerance there is no blood in the stool, symptoms are gassy, bloating, stomach ache and such.
6. I'm not 100% sure about the test to see if she's over it. I know there's 2. It's my understanding that they check for blood, then do a milk challenge where they give milk product, then do another check for blood.
I hear you on the food! I'm a big cheese lover, I miss it like a cocaine addict misses his drugs

. You do learn to love other foods. The first food I went nuts on was peanuts for some reason, couldn't get enough when I cut out milk!
Let me know how it goes once you make the changes and how fast you see results,
Marian