Adobe Flash support for portable apps

For FirefoxPortable:

First check if addon is disabled in about:addons (Firefox specific URL) and select the tab on left labeled "Plugins". If Flash is installed their should be an entry labeled "Shockwave Flash". Disabled addons will be towards the bottom of the list. Set it to either "Ask to Activate" (recommended) or "Always activate" to use. Refresh any open page with Flash content. If entry is not there, then Flash is not installed as a NPAPI plugin (which Firefox uses) or is not detected for some reason.

Have you tried installing it as PlayFlash from the firefox addons site. This requires no admin rights and applies only to your portable Firefox since its an addon.
For 32-bit https://addons.mozilla.org/en-US/firefox/addon/playflash/
For 64-bit https://addons.mozilla.org/en-US/firefox/addon/playflash-64bit/.
The Addon version make it easier for FirefoxPortable users, provided you don't use FirefoxPortable in both 32-bit and 64-bit modes. Browser requires a restart after installing addon. I recommend the addon version only if you disabled 64-bit from launching or are sure its only going to be run in 64-bit mode. Details for disabling FirefoxPortable 64-bit mode can be found here: https://portableapps.com/support/firefox_portable#32and64

If the addon method is undesirable because you need to be able to run Firefox in both 32 and 64-bit modes:
You can also use flash already installed from the system by copying certain dlls to the "FirefoxPortable/Data/plugins" folder, but the plugins must be 32-bit if Firefox is run in 32-it mode or 64-bit if run in 64-bit mode, copy both 32-bit and 64-bit plugins if unsure. The flash DLL will be named something like "NPSWF32_25_0_0_127.dll" (32-bit version) or "NPSWF64_25_0_0_127.dll" (64-bit version). The folder to look in varies by Windows OS version. For Windows 7 64-bit its "Windows\SysWOW64\Macromed\Flash" for 32-bit flash and "C:\Windows\System32\Macromed\Flash" for 64-bit flash (yes the folder names for 32-bit and 64-bit versions are deceptive) The Firefox specific URL of "about:plugins" shows detailed information about each plugin currently loaded including its path (most of the time).
Copying the DLLs to the "FirefoxPortable/Data/Plugins" folder will allow you to use whatever installed version of flash, which may still need to be enabled in addon settings. If Firefox is opened during this, restarting browser is necassary to detect the plugin. The DLLs are, however, might be useless on PCs that do not have Flash installed on them.

Not sure about Google Chorm but it should come with its own flash plugin (PPAPI plugin, not a NPAPI plugin)
The Google Chrome specific URL "chrome://flash/" should bring up details about Chrome's flash plugins, being stored at "GoogleChromePortable\Data\profile\PepperFlash\25.0.0.127\pepflashplayer.dll" (version number in path "25.0.0.127" depends on version of flash.)

Currently researching about enabling and disabling flash in Chrome.
To enable or disable flash:

1. Go to settings
2. Scroll down the bottom and click "show advanced settings"
3. Scroll to "privacy" settings and click button labeled "Content settings"
4. Scroll to Flash section of popup menu, choosing either "Ask first before allowing sites to run Flash (recommended)" or "Allow sites to run flash" to enable