Hi,
Okay so there are a few compatibility issues. First I'll tell you whats okay.
-1 bristlenose pleco
-6 bronze cories (they will love to have a shoal of 6 =D)
-6 other cories (love to be in a shoal, good job =D)
-6 guppies
-6 neons (love to be in a school, good job =D)
-1 blue mystery snail
-6 danios (what type though are you talking about? pearl, zebra, giant..)

Now my concerns are the chinese algea eaters mailnly. You might be okay with one of them, but personally, I wouldn't add them to a tank with very peaceful cories. So if I were you, I would veto the chinese alagea eaters because they are an aggressive species. As for the hillstream loaches, its not compatibility I'm concerned with, its just they have different temperature requirements and high oxygen requirements. Hillstream loaches generally like the water to be around 68F-75F, while the other fish in the community would pefer the temperature to be around 76F-80F. So I would also veto the hillstream loaches because they need cooler water with very high oxygen levels. Now last but not least, the gold loaches. So I'm not 100% familiar with gold loaches but I tried to do some reading on them and discovered there are a lort of gold loach types like the the gold dojo loach, gold zebra loach, gold weather loach. So if it is the gold dojo loach you are talking about then 6 of them should be okay with your 12 cories, they should have a fair amount of territory on the bottom, just be sure to have a lot of spots for them, though they wouldn't make the best fish becasue they liek the water to be about 68F-76F. If its the gold zebra loach your are talking about then I would say yes on them, they are very peaceful and you can keep a school of 6 and they like the water to be around 76F-84F, which would be perfect for your tank. The gold weather loach is a no though. Also, for a type of cory, I would recommend peppered coeis, they are a little bigger than the bronze, but my 3 would school with my 6 bronze cories and they are quiet cool looking and easily available. So if you follow my advice, this is what your tak will end up like.

Botton Dwellers: (18)
-6 Bronze corydoras
-6 Peppered Coryforas
-6 Gold Zebra loaches
(be sure to provide very fine gravel substrate for they all have delicate barbels)

Mid/Top Water Dwellers (18)
-6 guppies (I would recommend male, that way no matter what the tank wont overpopulate with guppies, plus they are really pretty)
-6 neon tetras
-6 danios (I recommend pearl or leopard) http://www.dkimages.com/discover/previews/970/45010774.JPG(they really are prettier tehn the pic, I had two with 3 pearl danios) http://www.elmersaquarium.com/image_fish/01%20danios%20pearl.jpg (same with the other pic, this isn't as cool or as pretty as they are)

Everywhere Else (1)
-1 blue mystery snail

So seeing as you dropped 12 fish, you might want to considering adding 2 more mid/top water schools of 6 fish or if you would please grant my wish please please add 1 male betta. He would love all that room and would be the perfect communtiy fish and since their are 52 gallons, he would have no problems at all with the male guppies. I have had male and female bettas in a 29 gallon tank before (not at the same time) with danios, platies, african dwarf frogs, swordtails, etc and they loved all the space and got along fine. So pretty pretty please add 1 male betta in your tank!! =D As for other choices, I would recommend platies but not mollies because cories do NOT like salt in thier water and mollies NEED it.
Well hope this helps!!!
Feel free to email w/ questions!!!