These are tough question to answer without getting overly technical, but let me give it a try.
Same tube type from different makes can sound different. This is due to subtle differences in characteristics due to variations in electro-mechanical design and construction.
A tube's characteristics is mostly defined by its internal geometry (electrode spacing, grid alignment etc.) and cathode emission character. Each make has a different design that ends up with its own set of peculiarity like certain inter-electrode capacitance (high frequency response), internal resistance (low frequency response for output tubes) or linearity (distortion).
So the same tube type from different manufacturer, dropped into the same circuit, can sound different. This is even more pronounced when comparing same tube types with different internal design (i.e. EL34 vs KT77 or 6CA7).
With pentode vs triode operate completely differently, so it's not something you can compare just in terms of tube differences.
Since pentodes and triodes behave differently, you will use them in different circuits. Generally speaking (and overly simplified), pentodes tend to have higher gain with worse linearity and frequency response than a triode. But you get higher output from pentode and extra gain can be use for higher NFB that you might not be able to afford in a triode design. So pentode vs triode is as much a comparison of circuitry.