the Fierce & the LintKing's Amber Bits

Benedict: Did not want to 'upset the status quo' too much. He didn't consider Eric as anything besides regent, but respected that Eric had a good claim. Perhaps he was evaluating the chaos that would erupt by displacing Eric, but the other side of that is how much Eric's planning and knowledge prevented that chaos. (With or without a capital 'C'.)

Caine: Corwin could have used Caine, too, but Caine knew his strongest position was with someone who didn't oppose him doing what he wanted to do... including being a pivot in the family strife. Might have had something to do with his own precedence, as well.

Deirdre: Opposed. Deirdre was made a prisoner... we don't know why. Probably because she didn't support his politics.

Julian: Didn't have any reason to like Corwin, but he was a just person and wanted Corwin treated humanely. (This was a change in Julian, one that Eric may have been the catalyst for, as well.) Eric, though, had the stability and position, and Jules was afraid of the redheaded trio: more strength against them was optimal.

Gerard: Mostly kept out of it, supported Eric because Eric had a good claim - after all, who really cared about the illegitimate aspect? When evidence of the foul play involving Corwin came up, he started to have second thoughts.

The major thing that supports a "spooky" Eric to me is how Oberon treated him, with the more-than-implied threats regarding fratricides not taking the throne... things like that. Was that in regards to Eric having a magical nature? Just part of the planning...after all, he mastered the Jewel by himself, too.