Spanning traffic from Watchguard Firebox M4xx series

Hello!

As the name suggests, I need to mirror traffic from a watch guard firewall, but it appears not to be possible. As per their user documentation.

Three questions.

1. Their documentation was from 2016, so might be outdated, does anyone have any experience with port mirroring on a Watchguard Firebox M4xx series FW, is it possible?

Before the firewall, there are a number of unmanaged switches. There is an unmanaged switch per area of the business, plugging directly into the firewall.

Port mirroring is what I'd usually do, but it's not possible from the switches or firewall and I want to use the least intrusive method.

Network tap is the next method I'm considering, but I've never actually used one.

1. Say there are 10 ports I need to mirror, how many ports need to be on the tap? Sorry if this is a dense question, I've checked around but can't actually understand how they work.

2. By that I mean, do they copy all Tx and Rx traffic they receive from a device they're plugged into? Or just from a particular port?

I appreciate anyone's help.

Please and thank you!