Corsair Carbide Series 500R and fans

I believe that case has 3 wire fans intended to plug into motherboard headers. They can plug into 3 or 4 pin headers. IT doesn't matter. The 4th pin is for fans that have PWM control. The first 2 pins are the power, the 3rd is the tach feeedback so the BIOS can monitor the speed.
A separate fan controller doesn't require a modular PSU. It simply connects to the PSU via a Molex connector.
If you can find a board with 4 system fan headers (even if one says Power Fan), you can easily connect all your fans to the board and let the BIOS or a 3rd party program control the speed. (except for the Pwr Fan one)

I can't figure out how to remove the plates from the optical drive bays.

I don't have a Corsair Carbide Series 500R White sitting in front of me to examine, but from the instructions it looks like they pop out like normal drive bay covers. Reach inside the case and feel for some finger tabs on the drive bay covers. squeeze them in slightly and push the cover out the front of the case. Better yet, remove the front cover and then you can see what you are doing. Usually there's a finger grip under the bottom of the front cover to grab. Gently pull the front cover off the case.

Lord, I have pretty puny fingers and I can barely get them in enough between the bay holder and the plate tabs to get the tabs loose one by one.

Can't you pull off the front cover of the case?

Not sure what you mean, but I got my DVD drive in there, so I'll worry about it some other day.

Aside from the strange circular standoff things in the case(I guess there's no issue setting the motherboard on them), There is one copper standoff in the middle that's longer than the rest. The extension is thinner, so it'll fit inside the hole of the motherboard?

Yes, the standoff that doesn't accept a screw is designed to act as a helpful guide for positioning the motherboard in the case. And it also helps keep it in place as you add the screws to the other locations. Just be sure you don't add any extra standoffs behind the board that don't belong. A common mistake is to install all the standoffs even if they're not needed. If the standoff isn't aligned with a hole, it can ground out or short a solder trace behind the board.

There's a video on Newegg's page (Overview tab) for that case that shows the removal of one of the front drive bay covers. It starts at about the 8:30 minute mark. Choose the resolution that matches your monitor and enlarge the video to full screen.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Most cases have a removable front panel. Usually you need to remove the front panel for access to the front fan(s). On all but one case I've ever built with, the front panel is removable by pulling it out from the bottom. Check and see if your case's front panel has a notch-out at the bottom for grabbing with your fingers. If not, it may be removed by a different method. Or it may be one of those rare cases that won't allow you to remove the front panel.

I seen a guy mention the round things are standoffs at the very top, so it is safe to place the mobo on them? Does it matter if it's the metal of the case sticking up as round things, or copper standoffs, it's safe for the mobo regardless?

I was going to mention the issues about filters at the top and side, but I just bought 2x 140mm filters for the top of the case(better than watching dust fall down there), and a custom side mesh specifically for the 500r.

Sorry to be a bother some more. To protect this case even more from dust, I was trying to find drive bay covers for the unused slots, since the case's bay shields have holes.

Curious, http://www.corsair.com/en/parts/case-parts/300r-5-25-ba... will a cover for a 300R fit in a 500R? It's a clip in cover as well.

Also, do PCI covers exist that have no holes or are filtered..? Would it be wise to do such a thing anyways? Like this http://www.gelidsolutions.com/products/index.php?lid=1&....

Those drive bay covers probably would not fit correctly. They only have one clip on each side. Yours have 2 clips on each side. But I wouldn't worry about dust with the original blank covers... they have dust filters.

The slot covers you linked to are fine, but their dust covers would act in keeping dust inside the case. I would avoid sealing up the vent openings of the case to completely. The more openess the better the air flow. I always try for a 'positive pressure' ventilation system. One in which air is always exiting the cracks and crevices. The only place dust filters are really needed in on intake openings. And possibly top openings if there is no fans.

I didn't notice any filters.

I was going by the video of your case on Newegg's site. It clearly shows the backside of the drive bay covers having a foam dust filter. The narrator even comments as such around 8:42 in the video. Most mid-range and higher cases have filters. I would be really surprised to find yours doesn't. Especially after Newegg shows them. Did you buy from Newegg?

If for some reason your case is different, you could try the ones you linked to. They're only $2 a pop.

Another question. I'm going to add Demciflex filters to the front and side of the case(possibly bottom too for PSU), and was wondering if the stock fans are good enough or should I use ones with a little more power to them? Since Demciflex has a slight air restriction. Or is the fact that the 500r has so much open airflow negate this issue anyway?

My experience with Demciflex filters is a big fat zero. So, it's best if I pass on that question rather than give erroneous advice. But I may look into those for my own next personal build.

They're pretty much a must for my place which is like an Australian dust bunny plague, lol. Maybe not that bad, but I don't want a GTX 670 to be sucking up a bunch of dust.