Replacing polarized Tantalum Caps

The schematic for the Stasis 2 & 3 shows polarized capacitors. Their appearance matches tantalum caps, (shiny gumdrops).

Research shows they should be replaced during repair or rebuild but there's no agreement beyond that.

* Mylar?
* Electrolytics?
* Polypropylene film?

Must the replacements also be polarized?

I see these: 0.15uF/50v (qty 2 per channel); 4.7uF/25v (qty 1 per channel).
 
I would definitely go for polypropylene caps. By the way I would replace that 6.3v 470uf electrolytic in the front end with a Elna Silk 2 cap. You have noticed that Nelson has a redesigned front end for that amp haven't you ?