VLANs: do all switches in a route have to support it?

All stations will be ale to participate in different VLANS, IF AND WHEN THEY USE TAGGING THEMSELVES. Non-.1q frames should be passed through by ancient switches, at least for as long as they don't exceed the maximum frame sizes (i.e. maybe you'll have to set MTU to 1496 on each tagging station A.

However, when you configure switch B's oort on switch A as an access port without tagging, and with an explicit single VLAN membership, as the second part of your question implies - then they won't be able to do so!

best regards Patrick

I would configure switch B port on A to have the VLANs i want my end stations to participate in. This though will require your end stations to have 802.1Q NICs.