Max of 4 nodes in any cluster. But I found from https://www.storagereview.com/node/3685 The FAS2200 series utilizes NetApp's Clustered Data ONTAP 8 operating system which offers continuous data access during scheduled downtime and supports scaling up to 69PB and 24 controller nodes.
End of Support date 30-Mar-2021 But I found End Of Support is March 30, 2020
Limited to 144 drives Agree
Technically limited to 1G ethernet. But I found from https://www.storagereview.com/node/3685 1Connectivity per controller: 4 x GbE ports, 2 xb10GbE, or 2 x 8 Gb FC using optional mezzanine I/O card
Check out https://hwu.netapp.com it's the go to for everythingNetApp/ONTAP/FAS/AFF/ASA/eSeries/HCI/etc. and things like maxes, mins and what's supported might change over time.
They extended the life of the 2240. Check out "End of life" in HWU.
Under "platform mixing rules" a max of 4 nodes of nas and san are supported. I think the line you're referring to in the storage review article is related to ontap in general (click the link and the same line is there too) and not the 22xx series, there are larger boxes of that gen that can scale that large, like the 62xx series.
The block mez card is only support in 8.1 and 8.2, not in 9.1
10GbE mez card (ports e1a/e1b), when running 8.3 (CDOT/ONTAP) and higher are technically reserved for the cluster connections. So yes they are there there, but technically can't be used for client access. It does show however that it'll work in 8.1 8.2, so I would think you can use them in 7mode (Maxes at 8.2) if needed.