I like all
Lich tries. The
Treasure Map is indeed one of the best storages for the counters.
I'm trying a similar build in U/B. However, I found that when I was using only a few creatures they tended to die quickly and the Vraska's Contempts and white's enchantments tended to hit the Liches. I mostly use disruptive creatures like
Kitesail Freebooter, to get their removal (with white I use it mainly for Settle), but that is rarely enough. I actually use
Sparring Construct,
Diamond Mare and
Chamber Sentry as additional token storages for the
Lich. These guys will die, but that is fine as I use them to fuel my
Sai, Master Thopterist and Secrets of the Mausoleum.
Phyrexian Scriptures is my only wiper, but works well with both Sai and the
Lich.
Secrets of the Mausoleum is the newest innovation I'm trying in this and it works well. It does not guarantee a
Lich on turn 3, but with
Stitcher's supplier it often helps to get a
Lich by turn 4. I also use
Lazav, the Multifarious to get
Lich's I've put in the graveyard back in play.