Not a dime, no. In fact, the combined economy of Xavax was barely greater than Itorunt alone, even at our height. Far less so, now. Calligus prevented any significant aid from Fallangard right up until Vix and Perdan declared war.
Sayuki quit. Said he was bored. Although how a 5v2 war can be boring is beyond me. So much room for activities!
As for Selenia, protip: She's a proud woman. She buried her husband before she was 20 years old, was killing Alpha's, litches, and hordes of rogues before Robb was even born. At his age, she'd overthrown a tyrant, subdued two neighbors, and forged an Empire. Before coming to Xavax, she'd never been defeated either in duels or on the battlefield. But you were right to fear. Selenia was elected on the platform that she would declare war on Alara. Ironically, plunging Xavax into the fires of war was the only way to save it from tearing itself apart. The only thing Robb could have done would be to appease her, thereby convincing her to attack Perleone instead. But by then, he had already signed an alliance with them. And Robb's rather proud himself, So when King Robb, who himself was a teenager at the time, demanded to be treated as her equal. Well, what followed is history.
The other problem she had with Robb is that she knew about his alliance-building. It became pretty obvious he was building a web that could eventually be used to invade the Imperium from all directions. He proved himself to be a surprisingly savvy diplomat, stunning really, given the marks against him. In trying to secure his defenses, he actually made himself into her biggest threat. What followed, again, is history.
