Yes, always!
The Ford rear end and Dana front ends (which are just repurposed rear ends by the way) don't always have a matched set, but the small differences are not a problem.
So you might have a 3.50 in one end and a 3.54 in the other, and that's just fine. But you can't even consider a 4.11 and a 3.50 because they are way too far off to be compatible.
At the best it would drive squirrelly in 4-wheel drive, at the worst it will brake something.
About the only time you do just a rear gear change is as a temporary test to make sure you like it before you spend the money on the front end. Lots of people have had to do it twice when they really did not like their choice of gears. It gets VERY expensive quickly, so doing just the rear on a Bronco is a good idea. Then when you know for a fact that you like it for your needs, then you do the front.
But no, in your case I would not go with 4.56's. I have an overdrive trans which lets me get away with it and still keep a friendly rpm on the highway. Even with the ridiculously low gearing for my tire size. About 29.5" in my case.
No, the 4.11 would probably be a better choice for 33" tires and a C4.
There is also a 4.30, but it depends on what you are going to do with the vehicle and how it's set up. More off-roading, the higher number is better. The more street, the more the lower numbers are better. But only up to a point...
If you have a carbureted engine that's old and tired with no mods, it likes the lower gearing (higher numbers) but if you've got a modern EFI setup with a good tune you can pull harder from a lower rpm and it runs well that way. Mine feels extremely strong, which is why I think it would tolerate the 3.50's. I know it would with the 31's, but I bet it would do just fine with the 33's as well.
Of course, it's kind of hard to tell for sure how much is engine torque and how much is gearing as it sits now. A 4.56 ratio is overkill-low especially for a street rig. It's definitely biased to off-roading and pulls so hard from a stand-still it feels unstoppable if you have traction.
Which is an issue on the street, as the tires break loose at the drop of a hat. Or the right pedal...
If you're going to spend 99% of the time on the street, plan to do some highway trips, and keep the C4, then going all the way to 4.56 would be somewhat overkill too.
If you intend to spend a lot of time off-roading and dune-jumping however, they might be just the ticket.
For comparison, a typical 33 inch flotation size tire (33x12.50-15 in other words) is likely about 31.5 to 32 inches overall height when mounted on the vehicle. Given that size here are the engine rpm ranges you would expect to see:
1. 3.50 @ 65mph = approx. 2500rpm
2. 4.11 @ 65mph = approx. 2900rpm
3. 4.56 @ 65mph = approx. 3300rpm
Number 1 is great on the highway, but would be sluggish off the line.
Number 3 is strong off the line, but revving too high on the highway.
Number 2 would be a good compromise.
When turning at those rpms on the highway, it sounds like your engine is screaming! Even at 3300 though, you're not hurting anything but fuel economy. However it sounds like it's close to redline according to most people who've driven their Broncos at higher speeds!
Even 2500 is a high rpm by today's standards, but common for an old truck. You have to keep a standard carbureted Bronco engine revved up to keep it feeling strong. And the 3-speeds of the C4 are always going to be a limiting factor. My trans with it's overdrive puts me at 2300-2400 rpm at the same speed, even with my smaller tires. Much more highway friendly, while still being super low for off-roading.
In the old days with my stock 3-speed manual and 32" rated tires, I spent a lot of time at 3,000 rpm and above when on the highway. Not a problem as long as you remembered your ear plugs and your gas cards!
Anyway, that's more info than you asked for, but it all plays in to your eventual decision on gearing. Normally I say change one thing at a time. Since we don't know how strong your engine pulls the best thing to do is keep the gearing as it is now, change the transmission and see how you like it.
But be ready to change the differential gearing if it's called for.
Paul