It's pretty much what you described. Our DS was evaluated at about age 2, primarily for speech delay, so one of the two evaluators was a speech therapist, the other was an OT if I remember correctly. They brought some toys and things they used, basically observing how he interacted and played. A large part of the eval was asking questions of me (mom) about his communication, habits, personality traits, milestones, interactions with older sister, eating and sleeping habits, birth history, etc. They were very in-depth in their questioning, with lots of probing follow-ups and clarifications. Because there were two evaluators, one did most of the questioning while the other was more free to focus on DS. They did a lot of observing how he handled two strangers in his house, having mom's attention focused elsewhere and how he communicated, what produced frustration in him and how it was handled, etc, but again, his main issue was expressive speech, so that certainly directed the focus of the evaluation. I was impressed with their ability to "read" DS, and they were very sensitive to overwhelming him or overloading him (he also had issues with sensory integration) and watching for signs that he was becoming fatigued. The whole thing probably lasted 2 or 2 ½ hours in total.
The report they produced was several very detailed and helpful pages of observations and suggested plans. For us, this was the entire evaluation. Overall, it was a positive experience, and resulted in DS qualifying for 6 months of early intervention, focused on speech/ expressive language; within a few months he was speaking well and discharged from the program.
