To capture remote network packets...and extend wireless?

(Long time visitor, first time poster- thanks for your involvement in this site, it has helped me tremendously over the years!)

I suppose the best thing to start with is a "simple" question, because there appears to be a LOT of reading on this subject, and I'm not afraid to do that work, but if what I want is not possible, I'd rather spend time on something more productive. That question is this:

Is it possible to capture data from wireless clients that connect to my network, given the following constraints:

1. There are many different types- iPhone, iPod, Android phone, Android tablet, PS3, laptops, and possibly more.
2. Assume I cannot install anything on the remote device, including a service (PC) or app (phone).
3. Assume that the captures should remain clandestine- no indication on the remote device.
4. Packet acquisition should operate through an application- if not WireShark, then something that is as understandable.

I would prefer the ability to maintain a route back into my system from the outside- for the sake of viewing my security cameras and accessing my home network. The way I've dealt with this in the past was through a DDNS service.

IF you all want to map out resources and tell me what to do step by step? PLEASE feel free to do so!!!! I understand, though, that these questions pop up all the time, and it HAS to be exhausting to keep seeing them, let alone to address them. If you do, imagine a world of good coming your way, and that if I could, I'd push the button that would deliver it to you!!!

I know my way around, but let's say just enough to get me into trouble. My major hang-ups with wireless networking ALWAYS end up to be an issue of a feature being called by a different name- seemingly everywhere I read or see it. Then there are the implementations of the router features that differ from one piece of hardware or software- to another. For example, I never would have imagined a week ago that plugging two wireless routers end-to-end using a LAN port (not the net port) would be a workable solution to some needs. I get crazy because I know things are possible, but I just can't seem to get there. So I'd rather start off knowing that there is a horizon to get to eventually. I apologize for the novel, too.

Without unnecessary detail, to ward off some inevitable questions- I am tracking for a number of reasons. These include parental control over browsing and sending data (video and still images), intrusions from unwelcome users (goal is to protect and verify my protection scheme, especially after extending the wireless coverage), and error-logging to figure out what causes nagging issues with some of these devices.

At minimum, I want to be able to see html requests- site visits. At best, I want to be able to capture, reassemble (if necessary), and export packets to view the images and video being sent over MY network.

Above is my first priority. However, as I'm putting this together, I would REALLY like to do so to support creation of additional wireless coverage in my home. The semi-detached home we live in is broken up pretty good- between initial access point to the furthest point I desire wireless coverage in. "Extending coverage" to me means that I do not necessarily need higher power- I need to get past natural barriers. I am hoping to do so wirelessly, but CAT5 can be run if it means that I can put everything I want in this post together and make it work.

Internet access is currently served through an Arris CM820A Cable Router.
To this is connected a Cisco EA4500 Wireless Router, Firmware 2.0.37.
Out of this, via CAT5 is my main PC line, and, an Ethernet Switch
The Ethernet Switch (Linksys SE1500) was added in a "far zone" to serve wired internet to a Security DVR and a Home Automation interface.
The Security DVR is a QSee model, and Home Automation Interface is from Insteon- allowing remote access to my automation interfaces in the home. There is also a CAT5 connected to the switch for the very occasional connection to my laptop and a PS3 gaming station.

My main PC is a Gateway Core i7 (930 at standard clock) with 9GB ram.
O/S on this is Windows 7 Ultimate 64. I also have Ubuntu installed on a drive for fun's sake, but have not used that in some time now.

The laptop is an older Vista unit, and I'll save some time by going over the rest of the devices that'll connect shortly.

But first- the extra routers that I have and am hoping I can use:
Linksys WRT54G, last running DD-WRT V24 SP2, mini.
Linksys WRT54G, last running the OEM firmware.
(Both routers are of the hardware revision necessary for tweaking with the least complication... I don't know how best to explain this without having them in hand.)
Belkin Wireless G Router F5D7230-4 V 4.03.03

Connecting Devices (Those higher up are the most important targets for observation. Some are mentioned only in case a potential conflict is noticed by one of you... something that could cause problems.)

Android 5S
iPhone 5
iPod (3? 4? I can find out)
HP Laptop, running Vista or 7 (I can find out)
Android 5S Active
Samsung Galaxy 4 Tablet (as far as I can tell via a mobile skulking app...)

Other wireless devices that will connect:
Wii
Insteon internet access (to RF and powerline device controls)
QSee QSDR04RTC Security DVR