Use tennokai mod you prefer.

Base crit chance is 23%
At max combo we get:
+440% from [Blood Rush] (+101.2)
+220% from set [Gladiator Might] and [Gladiator Vice] (+50.6)
+110% from [Galvanized Steel] (+25.3)
Total crit chance at 12x combo: 23 + 101.2 + 50.6 + 25.3 = 200.1% what means orange crits.

Base status chance is 21%
+120% from [Galvanized Elementalist] after 4 kills (+25.2)
+440% from [Weeping Wounds] at 12x combo (+92.4)
Total status chance at 12x combo: 21 + 25.2 + 92.4 = 138.6%

I can be wrong on critical multiplier calculation, but total crit multiplier should be like that:
1 + 2 × (3.4 × (1 + 120%) − 1) = 13.96x
Where 2 - orange crit multiplier and 3.4 base multiplier, 120% from [Galvanized Steel] after 4 kills.

Also we have passive which give us total +120% heat, it spreading in AoE by Melee Influence.

Naramon for keeping combo. Also if you use melee as main weapon, you can take primary with Primary Dexterity and secondary with Secondary Dexterity for boosting combo time.