As the title implies, I am asking this question in regards to the Cavalier class' alternate abilities and how they interact with the human favorite class bonus.
At level 5, Cavaliers gain the Banner ability, with boni to saving throws against fear and attack rolls on a charge. As of rather recently, some additional possibilities have been added in the form of Alternate Banner Options - which are treated as the Banner ability as per the rules. Let's use one of these as an example.
Jinx Standard gives the following benefits from the Banner to affected allies at Level 5:
+1 to CL checks to overcome spell resistance (increases by +1 at 10th level and every 5 levels thereafter).
+1 to the DC of Hexes, as well as Necromancy and Enchantment spells cast.
(well, there's also +2 to saves against damage-causing spells at level 14)
Now, Human Favored Class Bonus gives a Cavalier +1/4 to Banner Bonus per level. As such, if we took this bonus at every level until the 8th, would we be looking at the following bonuses given by the alternate Banner:
+3 to CL checks to overcome SR (increases to +4 at Level 10, and +5 at level 12 if we continue taking the favored class bonus)
+3 DC to Hexes, as well as Necromancy and Enchantment spells
The question is, am I correct in this rules interpretation, and is a Human Cavalier thus a Witch's best friend?
And as a bonus question, would the Human Favored Class Bonus apply to the bonus gained at level 14?
As written it looks like it works the way you think it does, and yes Cavaliers can be great friends with a witch.
HOWEVER
You've missed something about how Faviured Class Bonuses work (also it's "bonuses" not "boni", but that's not really important).
You can't take a FCB that increases "X" until you have "X". Thus a regular Human Cavalier can't take their FCB at levels 1-4 as they have no "Banner" to increase. You would begin taking your FCB at level 5 when you get access to your Banner class feature, so by level 8 the FCB would be giving all of your Banner bonuses a +1: +2 to CL checks to overcome SR (increases to +3 at Level 10, and +4 at level 12 if we continue taking the favored class bonus)
There are three caveats to this.
1. I think you can retrain FCB, so you can probably do that. I don't really use retraining rules, so maybe check with someone else.
2. The Standard Bearer archetype gets Banner at level 1, so they would be able to make full use of this FCB and Banner options.
3. I think this is a fairly common house rule, but maybe ot's just my group. We've ruled that you can't take FCB options that would Give you a bonus before you get the feature. Thus you couldn't take the FCB at levels 1-4 (because you'd end up with a +1 at level 4, and you don't have Banner yet), but you COULD take it at levels 2-5 (because you'd end up with a +1 at level 5, when you get your Banner). Again this isn't official, but it would work if your group agrees.
I think we did that house rule because some Paladins get +1/2 something to Lay on Hands, and it seemed kind of arbitrary to make them wait 1 level (there were other similar options with +1/3 to something they get at level 3 or something, but you get the idea).
But yeah you don't have to use it. I'm sure there are ways to unbalance it fairly quickly.
1d6 becomes 1d6+2
Thank you for your answers, I will seek a GM approval on these matters to keep things simple where necessary.
I will point out, however, that Favored Class Bonus is explicitly not retrainable or changeable if following RAW. But looking at the rules and suggestions here, there seems to be an odd workaround of taking the Standard Bearer Archetype at first, and then retraining it at level five to something else if desired. This would seem to allow a continued use of the Favored Class Bonus.
That.. honestly seems more cheesy than anything. I'd be careful going that route as you may not get the outcome you desire.
As I said, it's more of an odd workaround that arises from following pure RAW rather than anything one should rely on. It's why if going with this kind of build, I would prefer to simply ask minor houseruling from GM to keep things simple and clean (assuming no Standard Bearer).