Will this build work properly?

You are better off buying your RAM in pairs, less likelyhood of issues. To answer your questions:

1. The major differences other than price is the type and amount of features

2. I would avoid 1333, but using 1600 or higher should be fine. I believ the article was aimed at those looking to overclock the RAM (didn't read the whole thing).

3. You should be able to go to the Gigabyte website and find out the comatible memory for your motherboard, or you can go to the memory makers website and use their configurator program to see what they make that is compatible with your motherboard.

4 & 5. Your PSU will be fine while you have a single GPU, but if/when you go SLI you will need a larger wattage PSU (around 850W)

6. You will probably need to buy a new OS since you are changing motherboards.

1. The UD5H has 3 X16 slots, you only need 2(or 1) Stick with the cheaper motherboard.

2. Ram is sold in kits for a reason.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards can be very sensitive to this.
That is why ram vendors will NOT support ram that is not bought in one kit.
Although, I think the problem has lessened with the newer Intel chipsets. Still,
it is safer to get what you need in one kit.
No game, by itself will use more than 2-3gb. 8gb for a gamer is the norm. But, I like 16gb anyway. Windows will keep more im ram, available for instant reuse.
If you buy only one stick, you will run in a slower single channel mode. There is not a great price difference between 1600 and 1866 ram. More important might be the cas number, the lower the better.
You want documented ram compatibility. If you should ever have a problem, you want supported ram.
Otherwise, you risk a finger pointing battle between the ram and motherboard support sites, claiming "not my problem".
One place to check is your motherboards web site.
Look for the ram QVL list. It lists all of the ram kits that have been tested with that particular motherboard.
Sometimes the QVL list is not updated after the motherboard is released.
For more current info, go to a ram vendor's web site and access their ram selection configurator.
Enter your motherboard, and you will get a list of compatible ram kits.
While today's motherboards are more tolerant of different ram, it makes sense to buy ram that is known to work and is supported.
Look for a two stick kit in the first place.
FPS performance will be largely unaffected regardless of ram speed.

3. Parts look ok.

4. A GTX770 needs a 575w psu. You can run any single GPU graphics card, including a GTX780ti with it.

5. For sli, you need a stronger psu.
Here is my canned rant on planning for dual cards:
-----------------------------Start of rant----------------------------------------------------
Dual graphics cards vs. a good single card.

a) How good do you really need to be?
A single GTX650/ti or 7770 can give you good performance at 1920 x 1200 in most games.

A single GTX660 or 7850 will give you excellent performance at 1920 x 1200 in most games.
Even 2560 x 1600 will be good with lowered detail.
A single gtx690,7990, GTX780ti or R9-290X is about as good as it gets for a single card.

Only if you are looking at triple monitor gaming, or a 4k monitor, might sli/cf will be needed.
Even that is now changing with triple monitor support on top end cards and stronger single card solutions.

b) The costs for a single card are lower.
You require a less expensive motherboard; no need for sli/cf or multiple pci-e slots.
Even a ITX motherboard will do.

Your psu costs are less.
A GTX660 needs a 430w psu, even a GTX780 only needs a 575w psu.
When you add another card to the mix, plan on adding 200w to your psu requirements.

Even the most power hungry GTX690 only needs 620w, or a 7990 needs 700w.

Case cooling becomes more of an issue with dual cards.
That means a more expensive case with more and stronger fans.
You will also look at more noise.

c) Dual gpu's do not always render their half of the display in sync, causing microstuttering. It is an annoying effect.
The benefit of higher benchmark fps can be offset, particularly with lower tier cards.
Read this: http://www.tomshardware.com/reviews/radeon-geforce-stutter-crossfire,2995.html

d) dual gpu support is dependent on the driver. Not all games can benefit from dual cards.

e) dual cards up front reduces your option to get another card for an upgrade. Not that I suggest you plan for that.
It will often be the case that replacing your current card with a newer gen card will offer a better upgrade path.
The Maxwell and amd 8000 or 9000 series are due next year.
-------------------------------End of rant-----------------------------------------------------------

6. I will not build again without a SSD for the os and some apps.
120gb will hold the os and a few games. With 240gb, you may never need a hard drive at all. Look today at the Samsung EVO.

Few games can use more than 2-3 cores, making the hyperthreads of the 4770K largely irrelevant. I would use a 4670K and use the $100 saved towards a stronger graphics card upgrade in the future.

If you do not have an aftermarket cpu cooler, you will want one for overclocking.
I would avoid the liquid coolers in favor of a air cooler. Something like a noctua NH-D14 or phanteks is as good as it gets.

If your copy of windows 7 is upgrade or retail, or if you are on windows 8, then you can keep your os.
If it is oem, your license is tied to the motherboard. But, ms is lenient on this so long as the os is not used elsewhere. It is worth talking to them at activation time.