multiple vlans at a single port

I don't see the difference between this question and ones you asked about two or three weeks ago.

YES, a single port of a layer 2 switch may be a member of several different VLANs. There can be a different VLAN for every mechanically distinguishable characteristic of the packet. In general, this includes whether the packet is UDP or TCP or which subnet the source is, but that would involve layer 3 capabilities and you have defined the situation as involving only a layer 2 switch.

A specific example is a Nortel Baystack 450, which is able to create VLANs based upon several characteristics, such as whether the packet is 802.2, 802.3 or SNAP.