Hello, hello!

I can't really speak to Lightoller at Dunkirk, so I'm just going to stick to Titanic and answer any follow ups you may have that may help you draw your own conclusions about both his actions in 1912 and during the war :)

Second Officer Charles Lightoller asks Smith, "Hadn't we better get the women and children into the boats, sir?". Smith gives the affirmative. Lightoller took the order to mean women and children only, while First Officer William Murdoch took it to mean women and children first, that is - in the absence of women and/or children, he could allow men to enter the boats. Lightoller would not allow them to enter under any circumstances as long as there were women and children still aboard- and knowing the passenger count and lifeboat capacity- there were always going to be women and children still aboard.

The only law here was that they followed Smith's orders, but how they interpreted that order wasn't set in stone.

So now we have to look at Charles Lightoller's situation. Thomas Andrews - after sounding the damage- had estimated Titanic had an hour, maybe a little more. Titanic struck at 1140 and the first lifeboat was launched at 12:45ish. It's already been an hour, and he's been told that this ship could at capsize any minute.

He begins to load, women and children only, but no one is getting in. It's important to remember that Titanic's sinking was actually quite peaceful up until about the last 10 minutes- even boring actually. Here and here are videos that show Titanic sinking in real time. Skip ahead to about 12:45am and you'll see she's noticeably slanted but still calmly settling in the water.

What's happening on the boat deck is that barely anyone is there, and those that are simply won't get in. Why would they? Titanic doesn't seem in any serious danger and she's too safe to actually sink, right? And even if she did, it might take hours- even days. Lightoller knows opposite and he's on a time crunch. He lowers away the first few boats from the boat deck mostly empty because he has no time to waste waiting for passengers to meander up to the boats and decide if they want to get in or not. His decision here is right- Titanic did actually sink before they were able to get off all her boats. There is, quite literally, no time to waste.

Secondly, Lightoller lowered the boats lightly filled but that doesn't mean he intended to set them off that way. To avoid what would be a massive rush to the boat deck, Lightoller loaded the boat, then lowered it to A-Deck so people could get on. Then, he sent two seaman to open the D Deck gangway door so he could fill the rest of the boat from D-Deck. The D-Deck gangway door is where you may be getting the "opening other avenues" information from, and while this didn't actually come to fruition (another big topic that's an offshoot of this I can talk about if you're interested), its original purpose was to add passengers- including those from third class who had 3 routes up, one of which came through D-Deck. He did this because he didn't want a mad rush and the chaos of 2200 hundred people each trying to enter a boat from the tight space that was the boat deck. He's trying to stop a mad rush to the boats and the chaos and danger that would guarantee when the reality of Titanic's situation sets in among the passengers.

Lastly, Titanic's lifeboats were drilled, lowered, sailed and weight tested (on Olympic). Lifeboats, however, are only really supposed to be filled to max capacity under the safest of circumstances- which Titanic was obviously not in. Lightoller also has to account that overloading his boats could easily make their lowering much more difficult, and should Titanic tip or even list heavily, kill more people than they save.

Lightoller is on a ship he's been told could fully capsize any minute, trying to fill boats with a light crowd who dont see the need to get in. He's also trying to give people an equitable chance of entering a boat without having to make it all the way to the boat deck from soon to be flooded D-Deck or even crowded A- Deck- which will become even harder as Titanic sinks further into the ocean and the rush begins- something he has plenty of evidence to believe could happen any minute.

I must stress that the fear of Titanic listing heavily, or even tipping was absolutely legitimate (and she was already listing slightly). The fact that she didn't is actually pretty remarkable. In an absolute twist of irony, because of how safe Titanic was and how well she was designed and how difficult it was to sink her- she sank incredibly calmly until literally the last few minutes. Lightoller, however, had every reason to believe he was about to be unable to lower any boats at all. I refer back to the two linked videos (albeit they have slight differences). Titanic's sinking was only really "exciting" in the last 15 minutes.

Let's jump ahead in history when Titanic's almost identical sister, Britannic, proved that both Andrews and Lightoller were working under correct assumptions. She sank in under an hour in a starboard list so bad that the few boats she was able to lower struggled to get into the water. They both made the right call.

Lastly, I want to talk about your source. Everyone draws their own conclusions from their own research and lots of Titanic nerds debate various aspects of the incident. Pellegrino is quite debated as a source, with detractors pointing out hazy, unconfirmed, or even just plain wrong facts in his work. I'm not issuing a judgement either way (I honestly haven't looked at his stuff in years), I'm simply saying that as with any research topic (and especially one that's as profitable as Titanic), keep looking for different work or better yet- go back to the direct source. Lightoller himself wrote a book, and his Inquiry testimony is excellent and telling in ways he himself doesn't even realize, which I suppose answers your question as to whether his actions were well known- very! :)

Hope this helps!