I started to work on "translation tables", to be delivered later this week, at https://www.mediawiki.org/wiki/User:Elitre_(WMF)/Sandbox2 .
(Looks like Min Nan can get interface translations, but not documentation ones.)
Kudos to Trizek for his suggestion to switch from color-coded cells (bad for accessibility) to small icons underlining progress, or lack thereof.

I started messaging translators for Phase 6.1 wikis at translatewiki.net, because interface messages always have a priority. I delivered around 150 messages manually.
Here's what a message looks like.
ATM I'm mostly targeting users with native, professional, near native or advanced knowledge of a language (for languages in which I can actually choose to do so), regardless of whether they've been recently active or not. Reactivation of any account is an interesting point of data anyway, and we can always contact people with less proficiency in the language later.
Values in the table can only be updated manually.
Daily progress can be tracked only for interface translations, via this page.

(To clarify, progress can be measured for all of those wikis for documentation as well, just not that easily. I'm thinking that checking once a week, or something like that, works.)

Ok, let's see:
cdo: translations in this language didn't exist before. Interface is currently 68.86% translated;
hak: same as above, now at 3.19%;
hy: went from around 95% to 100% and all messages are up to date;
sh: went from around 83% to 98.60% and all messages are up to date;
xmf: went from around 42% to 79.24%.

Between yesterday and today I looked for more translators for some wikis in the Phase 6.1 group which are still at 0%, and messaged them.
I updated an office wiki guide with related resources.
Finally, I re-evaluated Phase 6 wikis based on their progress with translations: roughly half of them have 0% (or slightly more) progress for the interface, and we'll point that out in future messaging.

Last check for Phase 6.1 wikis:
cdo: was 0%, now 78.22%
hak: was 0%, now 3.38%
hy: was 95%, now 99.58%, and all messages are up to date
sh: was 84%, now 100%, and all messages are up to date
xmf: was 42%, now 78.65%
nan: was 0%, now 1.06% .

You can see graphs at https://translatewiki.net/wiki/User:Elitre_(WMF)/Phase_6.1 and compare spikes to the activity I reported here (first round of messaging, second round of messaging).

It's probably worth noting that there was no improvement in user guides' translation. While this partially makes sense (after all I'm targeting translatewiki users, who may not even have an account at mediawiki.org or any interest in creating one), this makes me also reconsider the approach toward other wikis. Interface and user guide are what we really care for, and this needs to be reflected in future messaging.