I am not as familiar with Burmese history as I am with Cambodian but funnily enough I am currently writing a thesis which examines ethnic cleansing in each area. So, far from an expert analysis on the subject I will give you some thoughts which might constitute an answer for you.

If I understand correctly your question is about the relation between KR ideology and the 'Burmese Way', as in.. do they share common roots? Which is a fair assumption given the numerous parallels between Cambodia and Burma.

To give you a short answer it would be; yes, they are in a sense 'related', but maybe more like distant cousins - or maybe a better analogy would be 'convergent evolution' where two different species evolve similar traits due to their environment. The big difference, among many, I would say is their relationship to the Cold War and their foreign policy. The two states certainly 'look' similar, but some of the parallels are more superficial than relating to the same common ideological roots. The CPK were far more 'communist' than the leaders of Burma. They were aligned with China in a fairly explicit way. I would go as far as to say that Burma never had a revolution to the extent that Cambodia did either, and the revolution that the KR implemented was far outside the scope that the Burmese ever attempted. Likewise the Burmese have always been pre-occupied with preserving the Union of Burma in regards to dismantling the states along ethnic lines - this has had a huge effect on their ideology, most notably the relationship that has been fostered between Theravada Buddhism and the military junta. In cambodia the opposite was true, even when you consider the links between some buddhist concepts and KR ideology (see an earlier answer about buddhism/Khmer Rouge ideology) and the CPK was keen to tear down Cambodian's relationship to the past. Cambodia's foreign policy was highly impacted by its relationship with Vietnam and the eventual war between them (and internal purges of the CPK in an attempt to ward off a supposed plot by the Vietnamese).

I've worked on three different answers to this question and I end up deleting them. You seem to be aware of the ideological palimpsest in Burma and Cambodia under the KR, as well as the relative similarities in history between the two countries... and there are some similarities to be sure. But in effect, these similarities provide quite different outcomes and are dependent on different structures. A lot of this stems from the condition each country found itself in following WWII. Its actually what I've come up against a bit when writing my thesis, I noticed lots of the similarities you have mentioned (and more when you look at the Rohingya/Cham minorities treatment) but like I said some of these parallels are just that - 'they never touch'.

I know this has basically been a meandering non-answer so I will give you one thing that directly relates to your question!

You say that you are unaware of any contact between the two, and wonder if you are missing something. Well you are! Burma was one of the few governments to that had a foreign ministry in Phnom Penh during DK. And as the CPK looked to broaden their international support in 1977 Burma's Ne Win became the first foreign head of state to visit Phnom Penh. So, I'm sorry but that is just about all I can offer you.

Maybe I can offer you a better answer when I have finished my research.