Yes, I think 'shares' might be troublesome. Even 'notes' has a legal connotation, though it's more of a civil law term, so probably less of interest to the government than to private parties (such as promissory notes, which are often called notes). For better or for worse, I think we should stick to 'play money' terms until regulations become clearer. The ideal terms would be some happy mixture of descriptive (e.g. coins) and fun (e.g. chips).
I do like 'slices'. Some other cool synonyms: chunks, doses, drags, bites, plums, whacks, rations, fragments, scraps, shreds, portions, atoms, flakes, slivers, drops, splinters, snippets, morsels, snatches. I'd like to buy some snatches, please.
For more playful terms (for 'shares' or artist-issued assets), how about jangles, jams, bling, skins, assets, dinero, hoohas, wampum, gravy, bread, scratch, chips, chords, riches...
Then there are the traditional 'coin' alternatives: bucks, bullion, reserves, mints, etc.
The concept of 'building blocks' might offer another metaphor: units, blocks, frames, bricks, parts, etc.