TOSLINK cables are for ADAT/optical SPDIF.

For MADI you usually need multimode fiber cable.
Nowadays, two multimode cable standards exist: OM3 or OM4.

In the network world, OM4 gives you more range, in the audio world this difference doesn't exist. With multimode cable, the distance between each of the devices may be 2 km, no matter if you use OM3 or OM4. But if you also have network devices in your company or at home in a project studio, then I would try to stick to one cabling standard. "Either OM3 or OM4" because you should not mix cables of different standards. So I would use OM4 in general, the price difference is "near zero".

With single mode, the distance between devices may be 10 km. As this is laser light, don't look with your eyes into it.
Multimode is well enough.

The devices without SFP ports have per default multimode equipped only on special order single mode (laser based).
If you have devices with SFP ports, then you can change the transceiver to be either multi- or single mode.
You cannot mix multimode and single mode. Either the one or the other. If your UFX+ has multimode ports (the default), then all connections need to be multimode.

Simplex or duplex is only the number of fibers. Whether a single cable or two cables.
So for connecting UFX+ and Ferro you need one duplex cable.
On the UFX+ side: SC plug
On the Ferro: LC plug (because it uses a smaller plug due to the SFP / transceiver).

To sum up, you require an OM4 multimode cable, LC to SC.
Like, e.g., this: https://www.kabelscheune.de/LWL-Kabel-L … 5-OM4.html

to 1)

https://usa.proterial.com/resources-dow … -om4-mean/
https://community.fs.com/article/advant … fiber.html

If you have no fixed in-house cabling that forces you to take the one or the other standard, then you can choose what you want, right? Ok. the difference might not matter to you (that you can use longer cable runs for 10 Gbit networks), as you use the multimode cable only for audio.
But the price difference is only small, and in some cases shops offer more OM4 cables because this is the later standard.
When ordering a cable in a shop, I wouldn't use the cheapest cable, make sure that you get a measuring protocol for each of the cables.

Now a personal, pure subjective thing … Moreover, I like the standard violet color more than the aquamarine color, cheers ;-)

to 2) yes, this is OM4 multimode cable with SC and LC plug for connecting one UFX+ (SC) with a Ferrofish Pulse 16 MX (LC).