Vsim-3978: Illegal assignment to class: Why is my override parameter not fully applied in my derived class?

Your problem is you are not using the correct factory registration macros.
Use `uvm_component_param_utils(k_sequencer#(SEQ)) and similar *_param_utils macros for the other parametrized classes.

You should have gotten a warning similar to

** at file.sv(5): (vlog-2181) Use of a parameterized class k_sequencer as a type creates a default specialization.

That is a clue that you had referenced a parameterized class without a parameter list.