No goalie has that value

Using those pieces or any other Kings pieces what would you offer?

Goalies have value when they provide significantly better performance than their cap hit. Bobrovsky has been one of the better goaltenders in the NHL recently, but no one is going to give up much in a trade for him because he makes $10M per season.

Shesterkin has one more year of a reasonable cap hit. After that, he's going to cost a LOT of money. More than Hellebuyck. I wouldn't give up significant assets for one season of affordable goaltending plus the right to give out a $9M+ goaltender extension.

What if he signed something in the 7-8m range as an extension? Helly is probably going to win the Veznia this year and he signed his extension this year. Maybe the days of the monster contracts for goalies are after Bob signing his, since then you have Helly signing his 8m contract Sorokin signing a 8m contract and Vassy at 9.5m. So it wouldn't be crazy to think Igor could sign something around an 8m contract.

6 out of the top 10 goaltenders in GAA this season had a cap hit of $2M or less. I wouldn't ever pay more than $6M for a goaltender.

What are the chances the Kings re-sign Roy?

I'd assume 50/50. But with an upcoming Byfield, Spence, Lizotte (probably Turcotte and a few other smaller) extensions, an unsolved Goalie situation and the need for a decent winger to skate in the third line with PLD, the chances are getting relatively slim. Clarke is ready to play his first full NHL season next year, so you'd have him to fill the gap.
I think Matt Roy deserves a bigger contract and there will be surely teams that will be ok to spend $5-6m, that the Kings simply cannot offer under the given circumstances

To give up Clarke, Fiala, Turcotte and a 1st rounder for a goalie, that will ask for around $10m per season after one year is insane. That wouldn't make any sense whatsoever for the Kings