Serious Sleep issues with toddler - ASD ONLY or Epilepsy too?

Hello all, Our toddler (29 months, boy) was diagnosed with borderline ASD, while it left us devastated and overwhelmed, we're trying to cope to the best of our capacity in every possible way. One inherent problem with ASD as we all know is varied sleep issues, in addition a vast number of Autistic kids also suffer from epilepsy and epilepsy itself exacerbates due to sleep disorders while sleep disorders get more intense due to epilepsy. Our toddler has certain symptoms which could be epileptic characteristics but they could also just be a result of autism, we're trying to establish what they really are. Before we expound on the core symptoms we'd like to clarify that we do realize that an eeg or a battery of eegs are the only conclusive way, but it has been exceedingly hard to successfully complete an eeg with him. After 3 failed attempts due to the fact that he WONT sleep through the process, we finally got it setup at home and it was a success and the report was clear but there is conflicting information out there about how irrefutable a single eeg is. We see a top neurologist in a couple of weeks but we've been given the following contradicting responses: A) A normal eeg does not rule out epilepsy, it only means that an event or episode did not occur during the eeg, this fact substantiates further eegs. - Reliable internet sources, information provided by accomplished pediatricians. B) Abnormal brain waves, which the EEG measures are present even when there is no activity (seizure). - A top pediactrician. A little information on our toddlers sleep patterns: He has always had sleep issues, it is very rare for him to sleep through the night (perhaps twice a month), and we've tried all the conventional methods including some advanced ones having paid sleep consultants considerable amounts of money. 1) He wakes about 2 times a night on a good night, sleeps 9 hours in all and takes about 10-15 mins to fall back to sleep each time. 2) He wakes about 3-4 times on a standard night and takes about 10-15 mins to fall back to sleep each time. 3) He wakes about 5-6 times on a bad night or SOMETIMES just twice but goes through an episode where his body sometimes tenses and his hands/legs twitch (no eye rolling, absence or loss of awareness) but he takes 2-5 hours to fall back to sleep in all so at least an hour each time. 4) In the worst case, when we miss a NAP (It has been immeasurably hard to force a nap each day no matter what) he has an episode where he's overly restless and keeps thrashing around from one corner of the bed to the other, neurologists and pediatricians clearly confirmed this not being a seizure which leads us to further quandaries. This is probably a result of being overtired but he takes up to 5 hours to go back to sleep. He is initially smiling away but eventually gets frustrated, cries and falls asleep due to exhaustion. Could this just be a case of his circadian system being completely out of sync? One point to note: So far, when we administer a melatonin supplement, he sleeps up to 10.5 hours at night and wakes about twice at the most, however he falls asleep within a few minutes, he is a completely different individual the next day, more focused, much happier and much calmer. What makes us think it could be epilepsy: He twitches his arms, legs, mouth and face (no eye rolling, absence or loss of awareness) constantly at night, in fact that is how we know he's in a deep sleep and dare to lay him on his bed. He twitches through his sleep at several times but mostly when just falls into a deep sleep and also when he endures what we refer to as the "attacks" (explained below). These subtle twitches he endures are very similar to myocolnic seizure activity we've seen on you tube but he NEVER twitches during the day except for when he naps. So they are isolated 100% to sleep time. The "attacks" where he's traumatized at times include his body tensing (torso mainly) and hands, legs and feet twitching over 30-40 mins, he keeps crying continuously, we know this isn't a seizure but it is some type of discomfort that we have no clue about. Could anyone please shed light on these sleep issues, especially relative to epilepsy or share similar instances which could help us understand what our baby is enduring? It is devastating and we feel totally helpless and worthless when he continues to cry without us knowing what to do or how to help him. As we prepare for international visits to leading neurologists, we are desperate to find a solution to alleviate his suffering at night in the interim. I apologize for the wall of text and thank any responses in advance.