That's where I think it gets quite interesting - and yes, the Communist leaders did lead military commands - but often those were as a result of their agitation from within academia, they didn't emerge from the army first they inherited it. I suppose the most obvious modern examples would be some of those African dictators put into power by the US and UK in opposition to communism; people like Idi Amin and Mobutu Sese Seko - as well as those right-wing invisible figures pulling the strings of power in places like Pakistan.
The reason I said 'historically' is for the further discussion you've outlined, I think liberal democracies have done away with that core group of people who like to agitate in favour of professional soldiers and so they've been forced into various 'brotherhoods' where they all stand in the woods and pretend to be soldiers. This certainly seems to be the case with the Far Right who attempted to grab the Capitol building. They might think they're military, but they're not and their tactical understanding was laughable. In other places where there is less discernment the military may still be a training ground - such people exist in Ukraine and in Eastern Europe more generally and should be more concerning. They're also very useful for fighting against Putin though.... as highlighted in the linked article.
Most of the leaders you've highlighted I'd argue are significantly right of centre, but they aren't far right leaders. Trump and both Bushes were constrained by democracies. Duke has been largely booted to the fringes of the US. Orban is interesting in his general flow from left-to-right and a bit of an anomaly; the Germans I'm less familiar with but I'm pretty sure Weidel is closer to the centre than many of her colleagues want her to be. Le Pen senior did have military experience, Le Pen current expelled him from the party in 2015 indicating she is perhaps a little more attuned to liberal democratic ideas (though not much). Yaxley-Lennon is well known in this country for being a bit of a twat and commands about as much political respect as I do. The Far Right here have struggled to get off the ground in anything other than recruiting hot-headed idiots at soccer games.
The modern (and effective) Far Right seems to be coming from a new place - and that's of growing concern. They've eschewed the Hitler and Goring model of uniforms and parades and gone full in with the Goebbels approach. People who understand the power of language, apply intelligence to messaging and who are far smarter at baiting people into tactical mistakes - I've watched everyone available to fall into their traps do exactly that.
Goebells was always the one to watch, always the most sinister of the inner-circle and the most committed. :o/
