Ok, I'm getting more and more confused now. What is the talk here about straps? What are they used for (or are these just straps you hang the camera around your neck with...if so, there are specialized versions of those?)
That was me, I think...
Yes, I am talking about a strap you use to hang your camera from your body, Blackrapid and Carryspeed are alternatives to the neck strap that put the weight on your shoulder rather than your neck (a lot more comfortable); the Spider system is an alternative that clips the camera to a belt, putting the weight on your hips. If you're carrying around a Rebel and kit lens, the weight isn't such a big deal...but if you hang a body + 70-200/2.8 from your neck, you'll likely end up with some discomfort or worse, and personally I don't like that much bulk dangling on my chest (although there are also chest harness options, e.g. Cotton Carrier).
Most of the neck strap alternatives attach to the camera via the tripod socket - and that creates an issue for quick-release tripod plates. There are options that don't use the tripod strap, e.g. BosStrap, but AFAIK they cannot be attached to the lens collar foot, which is a far better way to carry a heavy lens from a strap (better balance).
Personally, I use Blackrapid straps. I have Kirk 1" clamps (Arca-Swiss type) on the emds of the straps, so I can simply attach the strap to the plates that are on my cameras and lenses, and easily remove the strap when I want to mount to a tripod/monopod.
Also, what are L-brackets...what are they used for?
An L-bracket provides a vertical mounting surface, so you can easily mount the camera to a tripod in portrait orientation, with better balance than using a drop notch on a ballhead, and the ability to do pano shots in portrait orientation. Great for photos, but I don't think that orientation is very useful for video shooting.
Just like camera base plates, there are 'universal' and camera-specific L-brackets. While universal base plates are ok, the generic L-brackets are not so good (they tend either block access to ports on the side of the camera, or stick way out to avoid blocking those ports).
So, will need a bracket for that...figuring one plate for the camera....and brackets for the tripod, monopod (to be), Rhino slider (to be delivered), and Optika steadi cam....
Seems you have one head and one plate, and are about to order at least three more things you want to attach your camera to, and you just got a lens with a tripod collar. That means you'll soon have 2 attachment points (plates) for 4 different supports (clamps) - and that's the sort of thing where you really want a QR system!
I had many plates and clamps in the Manfrotto RC-2 system, plus 4 Blackrapid FastenR-T1 lugs, and I sold them all when I switched to the Arca Swiss-type system. But...I have no regrets about switching. You're basically at the jumping off point now. So, you're asking these questions at the right time, before you spend a lot of money on one system and then outgrow it.
Down to specifics, it looks like the fluid head you have can only take an RC2 (aka 200PL) plate - that's pretty common for many of Manfrotto's heads, only their higher end ones can take a non-Manfrotto clamp.
The Rhino slider needs a head (a ballhead, I'd think), and the Opteka steadycam-like accessory needs a clamp. So in both cases, you can choose your clamp.
The monopod/head you link uses a Manfrotto 501PL plate. That's a different plate than the tripod fluid head you have, and the two of them are not interchangeable. So right there, you see...even within the Manfrotto line, you've got two different plate+clamp designs, and you have to unscrew one plate and mount another to go from tripod to monopod (or stack a clamp on a plate, see below). That completely defeats the purpose of a QR system, IMO, and is why the Arca-Swiss system is better.
You have some choices ahead, and probably more research. One tip - Kirk makes 'conversion' clamps for Manfrotto. Their SQRC-3157
is an Arca-Swiss compatible clamp that will take any AS-type plate, and has a Manfrotto RC-2 plate built into the bottom - you could clamp that into your tripod head, then clamp any AS plate into it. The SQRC-501PL
does the same thing for the Manfrotto 501 clamp on the monopod you link. Both are available from Kirk or from B&H/Adorama. If you clicked the links, you noticed that unfortunately they aren't cheap (those two conversion clamps together cost more than the monopod/head combo you linked).
The Manfrotto systems are cheaper, although the quality isn't as good and as stated, they aren't cross-compatible within the lines. The workaround is to pick whichever of the clamps (RC2 or 501PL) you have more of, then use the plates for that clamp on your camera/lenses. Assuming that's the RC2, the way to convert between the RC2 and 501PL, for example, is to get a clamp for the RC2 (called Manfrotto 323), then connect a 501PL plate to the bottom of that. Then you drop that plate+clamp into the monopod head, and attach your camera or lens to the 323 clamp.
Once you decide on Manfrotto vs. an AS system, we can help with clamp choices, etc. There again, though, the Manfrotto is the 'value' option - the 323 clamp is $33, Kirk/Wimberley/RRS screw clamps are in the $60-80 range, and RRS lever clamps are mostly >$100.
Hope that helps...