Leaky capacitors need replacement?

Absolutely.

On the electrolytic on the boards, I would recommend Panasonic FM, Nichicon KZ or FG or Elna Silmic II.  These caps all perform at a very high level. 

Are you saying to replace the electrolytics with new electrolytics or use something else? These are right off the AC mains between the IEC plug and the rest of the amp.

These parts are being used in the DC Blocker inside the amp.

They should be replaced with the same value and voltage. @timlub has mentioned some nice quality parts to replace yours, which have a tendency to do this long before their time.

I don't know if I can fit those fancy caps in the same spot -- they are rather large!  I probably need to get something the same size so I can run the leads where they need to go (my amp is point-to-point wired).

Aren't electrolytics generally frowned upon for audio use because they leak and have issues with heat?  My understanding is that they are only used because they are physically small for the farads/volts compared to other types. Is this right?

I should add I would be most happy to put something in that might last longer.