Loose Bolt

Iron bank should have another assets like land, ships, right to collect taxes and custom revenues, monopolies of selling or buying certain stuff (like salt) and they could even take their cuts of existing businesses. So there is a possibility that IB would survive even if Westerosi won't pay back their loans.

Another possible way to leave cities or towns with harbour are ships. After all thanks to poor food, water and diseases aboard those ships there should be very huge demand for new blood for crews of those ships. If that person is lucky enough to survive he should learn something and even became hand of the king.

Another thing is that queen Visenya outlived her brother and I suspect that she actually "micromanaged" more than Aegon even he was still around. So it is possible that incompetence of next kings was actually her fault.

If next lord of Rock is somebody else than Tyrion all those papers signed by him are worthless.

As a king he could have knighted himself.

I suspect that without a Stark there would be either major civil war in the North about who would rule or there would be many petty and hostile "kingdoms". So Stark in WF is a glue that keeps North together.

How secure are Tyrells? After all there are many houses who think that they had better claims to Highgarden than that house. So now when Tyrells has a lot of problems there is a possibility that there will be rebellion against those upstart stewards.

The World of Ice and Fire - The Targaryen Kings: Aegon III When Aegon the Younger came to the Iron Throne in 131 AC as Aegon III, after the death of his uncle Aegon II, the realm may well have thought that its troubles were done. Aegon III's supporters had defeated the last of Aegon II's host at the Battle of the Kingsroad and had full control of King's Landing. The Velaryon fleet once more served the Iron Throne, and the Sea Snake would surely help to guide the young king. But these hopes were built on sand, and this period was soon known as the False Dawn. Aegon II had sent men across the narrow sea in search of sellswords, and none knew when or if those would return to avenge their king. In the west, the Red Kraken and his reavers ravished Fair Isle and the western coast. And a terrible, hard winter—first declared by the Conclave in Oldtown in 130 AC, on Maiden's Day—had taken a firm grip on the realm, and would last for six cruel years. Young King Aegon III. (illustration credit 59) Nowhere in the Seven Kingdoms did the winter matter more than in the North—and the fear of such a winter had driven the Winter Wolves to gather beneath the banner of Lord Roderick Dustin and die fighting for queen Rhaenyra. But behind them came a greater army of childless and homeless men, unwed men, old men, and younger sons, under the banner of Lord Cregan Stark. They had come for a war, for adventure and plunder, and for a glorious death to spare their kin beyond the Neck one more mouth to feed.

I suspect that most of those Cregan's men were "hunters". Or people who would during long winters sacrifice themselves to save food for their relatives. So very few of those men returned to North with lord Cregan but they chose to stay in South.

I suspect that Master of Laws main duty is enforcing laws in King's landing. Or he is master of gold cloaks and so Sheriff of KL. But he is not a judge. After that is king's main duty.

Roose is paranoid so nobody in Dreadfort would even take a leak without his direct permission. Or he was never totally loyal to Robb.

Could someone inherit or hold lands of landed knight without being a knight?

Another major mistake was that the North did not have any navy. After all IB had "always" raided western shores of the North. So first thing any sane new lord of Winterfell should do is to start building a navy to Sunset Sea. If that navy had existed Tywin would have to keep more of his men in the Westlands to stop possible invasion from North via those ships and IB would had invaded much richer lands instead of poor North. Or Riverlands would have had much better chances to stop invasion from west. Actually most likely there would have been "only" some raids. So if the North were a sea power story of SoIaF would be totally different.

About house Dustin. 1. Who is heir of house Dustin? Or was that LORD Dustin (who signed a letter) typo? 2. What are the words of that house?

I suspect that E.T just wanted to ring home.