Troll is paralyzed and it is another character that deals with holding it, so there is no need to use Telekinesis in combat maneuver mode. Sustained Force should suffice:
A sustained force moves an object weighing no more than 25 pounds per caster level (maximum 375 pounds at 15th level)
If spellcaster is strong enough to hold weigth of both creatures and their gear, it might work: Troll can make will save so it is no longer subject to the spell. If he succeeded, he still is held by PC, so if character is strong enough to hold that troll with it's gear, troll's save does not change much.
Once the troll is mobile again, you must resolve combat maneuver between it and spellcaster or PC who was holding it. If I was your DM, I would allow both PC to try and count win if either succeeded.
Note that a normal troll weighs around 1000 pounds, so unless aquatic ones are much lighter for some reason, the spell can't lift it alone - and definitely not along with the PC + gear. Adult Scrag (Aquatic Troll) is Large Humanoid, so it should weight about the same as other trolls. Moss trolls are Large, and weight about 100 pounds, being extremely thin, and in the other place they weight 550 pounds, so huge variation in troll body weight exists.
Some magic items may, of course, help with telekinesis and somehow increase it's limit. Only spellcaster's player and your DM know for sure.
Cone of cold
By Pathfinder SRD Cone of Cold description, you need the Mythic Cone of Cold to keep creature in ice. Regular one cannot do it, it only deals damage, but is too short to actually freeze anything. Also, it does not immobilize creature completely:
Any creature that fails its save is partially encased in ice, reducing its speed by half.
The thickness of ice is not given directly, but it is provided in more useful format - what's needed to destroy that ice:
Destroying the ice requires a successful Strength or dispel check against the spell's DC, or dealing bludgeoning or fire damage equal to 1 point per caster level to the creature.