You're right, Taurus Dark Region OX-U c2-9 is not a good candidate because of the ice presence.
For TS containing Ammonia World: yes they all are between 100 and 200 Kelvin. However, lot of AW close to merope are >200K (Mel 22 Sector OK-L b9-2, Pleiades Sector CB-X c1-11, Pleiades Sector GG-Y c4, Pleiades Sector DG-X c1-9 or HIP 23744) but none host TS. I've noticed what you've scanned, useless to do it twice. I'll go for all the Aries Dark Region HR-W d1-55 moons for the next days.
Last thing, I wonder if you scan a barnacle that is in the same system of a TS, does it make a POI for this base. Since the 2.4 update, scanning one barnacle shows every other barnacle and scanning TS show all the other barnacles in that system. I've already tested it here (BTW, all the barcacles of my scan are yet to be discovered and archived) :
https://i.imgur.com/JHF44hg.jpg
Maybe, if we found a barnacle instead of a new TS, scanning it will show undiscovered TS ? ... to be tested in barnacle and TS dual systems :
Hyades Sector AQ-Y d81 C 2
Pleiades Sector IX-S B4-4 A 6
Pleiades Sector GH-L b8-0 A 6
too much things to do I fear...