I'm soliciting recommendations, for vocal use, in the area of
inexpensive
1. tube mics

The tube mics I know which get you what I think you're describing are
not inexpensive. Solid state mics which will flatter voice are less
expensive, though still not cheap.

2. tube preamps

The sound you're talking about is not the result of having a tube in
the circuit as much as a result of having a transformer or two in
circuit.

3. processor?

You mean the Behringer thing you mentioned? No, the mic & preamp make
the sound. No amount of convolution processing is ever going to make an
SM57 plugged into a Mackie sound like a U47 plugged into a Helios pre.
Just isn't going to happen. Get the sound first, process later if you
want.

4. Pros and cons of the above three approaches

You need to listen for the sound you're after, not concern yourself
with the circuit design. What you're descibing can be achieved with
solid state equipment. It's not the tubes, it's the overall circuit
design, which usually involves transformers. Remember, Neve preamps are
all solid state, U87s are all solid state.

Scott Fraser