We found a Ram Mount cup holder worked on my husband's F3. I attached it to the end of 1 arm. It was self leveling, which allowed him to recline without spills. We had a variety of long straws. Tervis cups with the straw lids were great and fit well.
Another cheap mod I made was to put a set of large command hooks directly on the back. We could then hang a wheelchair bag or backpack on the chair. They never came off the entire 3 years he used the chair.
Permobil lights are stupidly expensive (over $1,000 for my older F5). I have a Permobil C500s VS wheelchair that has factory lights (paid for by insurance).
I have 3 other Permobil wheelchairs without factory lights. For each of those 3 wheelchairs, I have installed a set of bicycle lights (CatEye HL-EL135 Headlight and Omni 3 Rear Bike Light set purchased from Amazon for $30).
The Permobil lights are much better. They provide better light and have their control integrated into the joystick module.
The bicycle lights work OK for me, but are hard to turn on and off with my diminished finger strength.
I continue to look for a practical, cost-effective solution that gives me the benefits of the Permobil lights at a rational cost. I have not yet found a solution, and I have looked hard.
There are aftermarket lights for wheelchairs. While those will probably provide adequate light, I have not yet found one that integrates with the joystick module of Permobil wheelchairs.
As for a cup holder, I have a Permobil cup holder, which was stupidly expensive (close to $100). I don't use it often, because it gets in the way of everything where it is designed to mount.
My “cup holder” is an inexpensive fabric water bottle holder of the type a runner or hiker might attach to their belt. You can find them at outdoors stores. You can probably find a creative way to attach it to the arm of your chair. I use mine to hold my cellphone.
In addition to the cup holder, I have a tray that Medicare paid for. Requires sitting up to use it. Slides on under the chair arms.
You might want to make a carrier-cover for it, so it doesn't get damaged when transporting it. B
My wife has an M3 with the Permobil light kit (which is absurdly expensive). Permobil wants $100 for two coat hooks for the back of the chair; I used some clamps I got at Lowes and cheap carabiners for about a $3 solution. The only difficult part was finding square M6 nuts and 1cm M6x1.0 screws to attach to the track. I think I got the nuts on eBay or Amazon and the screws on Amazon.