To be honest Ice isn't that good type in OU,if u see no Ice pokemon is in that tier and that won't work at all but if you have fun with it,then just go for it. I will still try to give you my opinion
based on my experience.
Some words on the team
-At a first look of the team,you miss the best ice pokemons imo,like kyurem and dracozolt.
-You could put Beartic with Swift Swim,to maybe use that rain dance on lapras,beside hydration.
Beartic also has 130 base attack that is kinda great
-You could also implement a Hail Team on that,as i said,with Dracozolt and Arctovish.
Here is are two teams that i have where u can check some sets:
https://pokepast.es/3da68788f24892a9
https://pokepast.es/5fca5d821f04ced6
Remember that the second team was to get some fun in RU,so some sets aren't that good in OU
-If i would choose i would just remove Sandslash,Rotom and Avalugg.
-You als have only one Hail setter (i only count Ninetales-Alola) i should replace froslass with Aurorus.
Some words on the sets
-That Avalugg set is kinda strange.
Avalugg is a good mon for 1v1,but that set is kinda meh,why would u air balloon ? U are not weak at ground so i don't understand that.
I can understand the rest of the moves but most of the times such a set doesn't work at all.
-Lapras
That set is okay but the atk EVs ?? You also forgot the nature.
You are running 3 special moves so just go for modest 252 spATK EVs.
I should also use the rest EVs in HP or in Defense,cause he isn't that fast at all.
Also the item,just go for Life Orb if u want to deal damage of Leftovers for more coverage.
-Rotom-Frost
This is also kinda good,not much to say here.
Maybe use Discharge and not Tbolt for 20% more chance to get para.
-Ninetales-Alola
Same as Lapras,i would use bulkier EV's cause it is the only one hail setter that you have.
And Jolly isn't good for Ninetales-Alola,you need to use Timid.
I would then go for 252HP EVs and 252 Spe
-Sandslash-Alola
You need to use Slush Rush to get that +2 speed and after Swords Dance to get some good sweeps.
I would choose for life orb as item.
-Froslass
Froslass needs 252 EVs in speed for sure.
Also 252 EVs in SpA when you have only 1 physical attack move..
You can use him as a setter with Spikes or you can try to keep him like this but a Hail Setter with Snow Warning is way better.
I would use Aurorus.
If u want to keep Froslass,use 252HP and 252Spe EVs
I will make some changes with different option that i told and i will late you the team here.
Ice Team + Aurorus - Dracozolt
https://pokepast.es/f7d5c0bcfd51bc07
Ice Team + Arctozolt - Dracovish - Beartic
https://pokepast.es/056dfdcffccd8e18
If u want to get some fun you can try something like that,but remember that you wouldn't get high in the tier and there is also the "Monotype" tier,but honestyle the Ice type is one of the worstest types.