On the
www.helpforkidsspeech.com/ site there is also a link to a "Speech Sound Development Chart" which shows at what ages kids are expected to make which sounds. Based on the chart, 50% of kids correctly make the 'f' by the age of 2 1/2 and 90% by age 4 and the other three sounds you listed are later developing. These sounds are made in Russian (I just looked up a Russian alphabet/pronunciation guide), so he would have been hearing them since birth (if the sounds weren't in his first language, then it would be more difficult for him to learn them now, and the school would have a stronger ELL/ESL case).
I can't believe there is a waiting list for speech therapy. If it is interfering with a child's education, they have a right to services. Maybe this waiting list is for children who are only misarticulating a few sounds - a specific number of sounds must be misarticulated in order to truly qualify for special education speech therapy (I think the number varies depending on your state or even school district).
Until you can get your son tested, the school should be able to provide you with "home therapy" suggestions, but that will be impossible now due to the summer break. They should also give you suggestions to slow down his speech and to help with the omissions (not saying some sounds in words).
Perhaps you could start a thread asking if anyone is a speech/language therapist and could give you advice/suggestions? Post it in the Russia forum as well as a place where others may read/respond.