okie you are generally telling my to breathe, so im going to try this the other way...lets see how well its goes...lol...
first off its YOUR wedding day...and when all is said and done everything is going to be how you imagined it (brunch included...if in the end its what you want..trust me)
...but remember with adam you guys started out that you didnt want the at home big ceremony and reception because that wasn't for you guys...so you planned this beautiful escape wedding ( and even if you left it as is it would be beautiful and nobody..not even "her

" could call it a sham ) but okay so he goes along thinking hes done planning..done spending money (remember he sees $$$$ every time you say " so for the wedding i was thinking...") and he panics...because now hes like okay thats XX dollars more that needs to be saved...and we all know thats not easy to do.
he wants this to be perfect just as much as you do...but he doesnt see it the same way.. most guys dont get it. lol
i honestly think you should look at this a couple of ways
talk to him again about the brunch...see if there are places that have more lunch than brunch and that have the steaks that he wants. ... but if hes so set on the steak- ask him if hes willing to move the ceremony time . i know he mentioned he doesnt want to just sit in his tux....so how about he doesnt? how about him and some guys get an early round of golf in? ( does he golf?) or boating ... or something of that nature to pass the morning
or if he refuses to move the time, then remind him that not all places that are on the boardwalk serve meat....plain and simple so what if the restaurant you are planning on going to is closed for renovation next year

(it could happen!)......remind him that brunch/lunch is less expensive than a dinner...also much less stressful than having to chase pepople around...as you have mentioned people will be at the parks and such and we all know you can get carried away when you are in line for splash mountain listen to brer rabbit..i know i do.... (esp. when the spot where the frogs are supposed to be living...towards the very end of the line.....so cute!)
either way i thnk you have plenty of time, of course i keep telling myself that we have plenty of time ( 14 months

) and it will work itself out....give him a few days to sit on it, then talk to him again...i do agree alcohol always makes the guys agree with whatever the demand may be...some "but imagine it this way" and also a good " i dont want the wedding to look fake" line may help