You're forgetting the most relevant section, the voltages. According to TH99 the board has settings down to 2.5V. That's far too high for K6Plus CPUs, but fine for K6-3 (non-plus) and a bit high but not dangerous if your cooling is decent for K6-2.
If you're trying to use unsupported CPUs, first thing to do is to distill those silly "use these settings per CPU type" tables into the actual multiplier and bus speed settings. Look at P75, P90 and P100. All use 1.5x multiplier, so whatever stays the same across all three is the multiplier. The setting that changes is bus speed. In any event, you have two bits per setting, so BF0 and BF1 for multiplier and 2^2 (4) settings for bus. That's bad news as it means you have 50, 55, 60 and 66MHz only.
Now, all is not lost: K6-2 and -3 400 and higher interpret a 2x multiplier as 6x. So you could run a K6-2 or -3 at 66MHzx6=400MHz, with 2.5V. See TH99 for the voltage setting and see a CPU that does 2x66 in the table you posted for the bus and multiplier settings.
Last hurdle is BIOS. It is highly unlikely there is a BIOS for this board that officially supports K6-2. How non-supportive BIOS react can vary from a correct MHz indication with unknown CPU down to downright refusing to boot. YMMV, just one way to find out.