Molten Silver Strike allows to add Solar Wind boosts to Mithral Current attacks and adds +5ft/4init level to their range. Whirlpool strike allows you to attack every enemy in your weapons reach. Steady Hand (Solar) adds 30 ft range to your attack. Do they work together to allow you to attack everyone in 35+ range?
Mithral Current strikes that allow you to attack enemies at range as a melee attack
(Molten Steel Strike description, emphasis mine)
Most Mithral Current strikes do not allow you to attack enemies at range as a melee attack. Whirlpool strike certainly doesn’t. The only strikes that this feat are applicable to are iron wave, silver wave, quicksilver wave, and mithral wave.
Steady hand adds 30 feet of range. Range and reach are different—range is only for ranged attacks, reach is only for melee attacks. Whirlpool strike is melee, and so you need bonuses to reach—bonuses to range, as from steady hand, do not improve it. Molten Steel Strike does not change this, because Molten Steel Strike only applies to the Mithral Current strikes that allow attacking at range. With Molten Steel Strike, you could use steady hand on iron wave so that it can attack out to your close range + 30 feet, but not whirlpool strike.
To improve whirlpool strike, you need options that improve your reach. The most obvious of those is to increase your size, though there are other options.