FWIW, when I was in the SCA I fought with my halberd at reach and at sword-range. Close fighting wasn't difficult once I learned how to do it properly and the halberd was just as effective. What was hilarious was that a number of fighters would think that I would be vulnerable at close range. They looked pretty shocked when I clocked them upside their head! Frankly it was less strenuous to fight in close. I just pivoted my hips and really torqued it up. Fighting at range always involved the risk of tendonitis as my elbows were got strained. I suppose if my forearms were stronger it wouldn't have been a big deal. But let me tell you that the hips can generate a lot of power.
I guess what I'm saying is keep it simple. Just make a feat that allows for close quarter polearm fighting with no penalties and no other benefits. The prereq should be proficiency and Str 13. Oh and allow it for all polearms and staves but disallow it for spears. Can't use those in close quarters.
As far as fighting with the butt, I'd say use the double-weapon rules. You can also put a pseudo spearhead on as a butt cap but realistically the butt is far more effective at parrying that actually damaging your opponent.
Hope this helps.