Yes, bias could be handled easily with zeners or regular diodes in the cathode.
A Mu of 50 is still kinda low and would take some drive in RF linear service compared to the common power grid tubes used today.
All of this is fine and good, but the big unanswered question is "how clean is the tube itself?" Most of the time we need to dig for IMD figures. Manufacturers will sometimes reluctantly send them out if pressed.
It takes extreme manufacturing precision and great designs to put out IMD numbers that are above -30dB 3rd order in RF linear service. This includes class B modulator service. Class C is another matter and not as critical.
Before anyone gets serious about these tubes, search out actual amplifier engineering tests by the company showing these critical figures.
It is not easy to equal an 8877, YC-156 or 3CX-3000A7, all of which were designed for high amplification and extreme cleanliness approaching and exceeding -40dB 3rd IMD figures in RF linear service.
My point is that the tubes may be cheap, but if we are to spend a lot of time and money building a FB amplifier, then make sure we have the best tubes available for the job. It may cost a little more, but WTF.
BTW, do you realize my whole shtick above is negated simply by running an SDR Apache using pre-distortion software? Linear amplifiers can now be dirty, but cleaned up with this technique...
T