Hi! DS1 started ABA 12 months ago and we think it has helped him a lot in so many ways.
In answer to your last question though some of his first ABA programs were to encourage copying (something NT children do as standard to learn speech, social cues, etc). An example would be saying "do this" and touching your nose, or clapping your hands, etc and your DC copying your action. This is obviously in the middle of lots of motivational play, with lots of rewards, so your DC sees it all as a game. This worked brilliantly for DS as through this he started actually watching what I was doing and copying, and then other people.
Another program focussed on matching identical items (put 3 items in front of DC) then give an item identical to 1 of the 3, then say "match". Once DS could match identical items, then we moved to non-identical (so they were matching 2 toy cars, but one was vtech, and one happyland for example)... Then matching pictures to objects (picture of car)... Etc which has now become matching pictures to words (photo of me, and the word "mummy")
There were and have been many more, but the programs will be tailored to your child's individual needs so obviously not all will be the same.
Interesting what you have experienced with SALT, as I was told it was not worth their time working on DS1s severe speech sound issues (at age 3 he started speaking, but everything was vowel sounds e.g. Mummy was "Uh-ee", though he could make the "mmm" sound when he said "more"... ). They said he wouldn't work with them in the intensive way needed due to his inability to engage for long periods of time, or follow instructions.
Using ABA techniques it took me 3 weeks to teach him to say "mummy". Once we both knew it could be done it snowballed.. DS1 now talks in full sentences, and while he still has some speech sound issues he can be understood by most people.... As he tells them word for word an entire episode of Thomas the tank engine 

Of course all our children are different and have different strengths and difficulties but my point is ABA helped DS to do something SALT said was impossible at that time.