The range of the Temple of the Hand's terraforming is dependent on the amount of Ice mana available in that city. I'm guessing that your capital is the only city with access to that mana. Try building some roads.
Priests of Winter never summon golems. Sometimes they can summon Ice Elementals. The two units look the same but are not identical. Ice golems are slightly stronger, but have no unitcombat and so cannot purchase any promotions with xp. (They can be taught promotions by Barnaxus.)
Ice Elementals are a normal, limited duration summon allowed by the Ice II spell. They are likely to appear in most games.
Ice Golems almost never appear in the game. They are basically a hidden lore Easter Egg. They are produced by an ability that only Barnaxus can cast, but only if under Illian control.
How might the Illians get the Luchuirp hero, you might ask? There are two ways:
The Snowfall (Greater) spell converts all White Hand units not belonging to Auric's team or his vassals to Auric Ascended's side. Barnaxus starts with the White Hand religion, and so is vulnerable to this.
There are also two versions of the Rebuild Barnaxus spell. One can be used by anyone in a Luchuirp city, and gives the unit to the city owner (in exchange for a diplomatic bonus if the caster is not of the same owner). The other can only be used by Auric himself, and lets the Illians control the special golem.
(I just now decided to change that prereq to the White Hand State Religion, so the Luchuirp could use the ability if they decide to serve Auric.)
(A note on the lore: When the Illians were completing the ritual which summoned Mulcarn into Erebus, the The Empire of Khrad'Ke-zun were the only ones who were able to oppose them. Their army of golems almost managed to stop the ritual, but were slightly too late. The God of Winter greatly admired the craftsmanship of the Open-Sky Dwarves, finding Golems more in keeping with his own precept than any living creature. He chose to take one of the golems from the army he defeated, and breathed life into it. That gave Barnaxus a rational soul and a divine spark, much like that which Kilmorph gave to the sculptures of Kheldon Ki in order to create Bambur and the rest of the the first generation of dwarves. This somewhat changed what Mulcarn admired most about the automaton, but he needed to do so in order to make the machine capable of deigning, building, and enchanting more machines like his former self. Barnaxus loyally served Mulcarn throughout the Age of Ice, building him an army of Ice Golems that fought alongside the Illians against Kylorin. Only after Mulcarn's demise did Barnaxus wander away and find the Luchuirp, the descendants of the dwarves who fashioned his mechanical body years before it was ensoulled. The Luchuirp had been only one of several allied tribes that made up the Kradh-Ke-zun, but the rest all went extinct during the Age of Ice. Barnaxus's Ice Golems likely finished off many of them. Perhaps Barnaxus felt guilty about this and chose to help rebuild the Open-Skiers' empire as penance. He refused to discuss anything that happened during the Age of Ice though, and might well remain loyal to the sphere of winter and its god. We don't find out in the lore of the game, as there it was only his broken pieces that were captured by Auric's troops. Rather than rebuilding a loyal servant, the Illians treated his pieces as a holy relic. Auric then extracted Mulcarn's last breath from Barnaxus, absorbing into himself a piece of the old god of winter in order to facilitate his ascension.)
In my mod, Auric also has the option to destroy the pieces of Barnaxus in order to hasten the completion of either The Draw or Ascension. That is probably more useful than a few Ice Golems, although it isn't possible until much later in the game.
The Summon Ice Golem spell does not require Channeling II, only Ice II. You cannot purchase Ice II with experience without Channeling II, but could start with the promotion or gain it in python.
Auric's 3 lieutenants start with the Ice promotions in their xml defines. Other priests of winter get Ice sphere promotions based on mana, the same as they would if they were mages
(High) Priests of Winter should be given the Ice sphere promotions based on the mana their owners control when they are trained. (As with adepts, those under Illian control also get Ice I for free regardless of the mana supply.)
These clerics cannot purchase Ice sphere promotions after being created, as I'd have to make to brand new promotions just to serve as alternate prereqs or also rish letting Ice mana be way to easy for priests and high priests of other religions to learn after Govannon teaches them a few spells.
Learning and growing into new abilities is not something really favored by the precept of Ice anyway. There sphere is largely about nostalgia, idealizing how things used to be and not wanting to change except to undo other changes.
None of these Illian changes are recent, so I don't see why they would just now be coming to your attention if you had played any other versions of my modmod in the past couple years.