First of all, Copeland mixes up Ryan and Krantz here. And he doesn't really explain why Sinclair outranked Majors Atombe, Kemmer, and the actual Krantz then. But maybe this is the retcon here.
That or he's mixing up Sinclair and Sheridan. Either way it makes no difference at all.
I see. I thought that was also from the system they were working from behind-the-scenes. Or was that officers only?
The ones with the patches that were the ship's patch (or the ships letter) are NCOs or enlisted. Watch 'Endgame' or 'A Call to Arms', there's quite a few of them wandering around on the bridges of the Apollo and Aggie (probably the same extras

) and you may also notice that one of them in aCtA is played by Marjean Holden, before she was cast as Chambers.
"I'll give you your Bath pips if I can keep my colonel eagle"? That doesn't sound very likely and is just asking for confusion. A much simpler and more likely solution would be to simply adopt a system based on navy officer sleeve/shoulder stripes, which are almost identical between the US and UK and are quite similar the world over.
You expect logic and sense to emerge from a Senate committee? The very fact that those insignia are in a way emblematic of those two specific nation's respective armed forces would probably have been part of a PR tactic to show that Earthforce had not lost it's traditions by homogenising everyone.
Actually, in the early days I would imagine Earthforce was just a few steps up from today's coalition forces and it wasn't until, say the early to mid 22nd century that they even started to integrate. Hence the odd holdovers.
Then shouldn't major be a crown instead of three pips?
Only if Earhtforce officers swear an oath of allegiance to the British crown. Somehow I don't think they do.
I read it, it just wasn't much help. It looks to me like it was intended to shoehorn major, lt. colonel and colonel grades into some kind of scheme after the fact, so they would be consistent with what had already been established on-screen. And there is no "reasoning" given, other than they come next, and there is also no reason given for why so many grades are needed.
Like I said, it was a letter in a Q&A type column so he could hardly have gone into too much detail.
I still think Major belongs between Lieutenant and Lieutenant Commander, like I originally thought. Some of the Majors we saw, like Lianna Kemmer, were WAY too young to be up that high in the ranks. You think she could have outranked, say, Sheridan? I thought not.
Besides, look how Major Krantz visibly deferred to Sinclair (even saluted him) in "Babylon Squared". Krantz definitely acted like Sinclair was *his* superior officer, not the reverse.
Some? Of the four we saw three were played by actors in their 40s or 50s.
Kemmer was head of presidential security, that's not a job you get without some significant degree of experience and seniority. However young she may have been, she clearly made an impression and climbed the ranks very fast.
It also might be worth keeping in mind what the attrition rate of the Earth-Minbari War would have done to the officer ranks. It's not so unusual for young people to get promoted fast in that kind of climate and though Liana was certainly too young to have served in that conflict, the sheer depletion of numbers would have meant there were plenty of spots to fill for ambitious young officers.
As for Krantz, the guy was clearly not in control and was in a state of near panic almost the entire time. I don't think the exactitudes of military protocol were foremost in his mind.
And Ryan was evidentially the XO of a full General and one of the Joint Chiefs of Staff. You really think someone just one paygrade up from a mere Lieutenant would get that job? I once worked as a civilian clerk in the RHQ of a mere artillery regiment and I can tell you that the CO, who was a Lieutenant Colonel had two adjutants, one a Captain, one a Major and another Major as his 2IC.
Do you really think a General's flagship would be left under the command of anyone BELOW the rank of Captain in the General's absence? Of course not, that's insane.