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I mean, as part of the cut-through processing, the VLAN tag needs to be analyzed. If the ingress port is configured to support VLAN tags, then the cut-through needs to wait to see that portion of the frame. Likewise, if the egress port is VLAN tagged, the frame will need to held until the frame's VLAN tag can be constructed.
So, yes, cut-through could work with VLAN tags, it will just add a bit of latency. It's up to the device vendor to determine how, and under what conditions, cut-though will work.
Some cut-through swtiches support "fragment-fee", which means that look at more of the header. Some (at least years ago), would use fragment-free dynamically (based on loading). So, again, it's really up to the device vendor. (BTW, "basic" cut-though assumes the whole frame will be received, but that's not always a valid assumption.)
