In case you're not already aware, you may want to review Typography refresh, its talk page archives, and associated discussions elsewhere (e.g. wikitech-l).
IIRC, that past attempt got negative feedback over its preference of non-free fonts over free fonts, and negative feedback because font names were being mapped to worse-displaying fonts than generic sans-serif on some systems or were poorly-displaying ancient versions installed by some application.
OTOH, if the target for Minerva really is only mobile devices maybe that makes some of that irrelevant, at least if you remove the pseudo-generic "Helvetica Neue" and the like.