99% of my D&D 5e rules questions stem from carrying 35 years worth of D&D rules in my head

How does multiclassing the Soulknife and Psi Warrior work with regards to how many Psionic Energy dice you get?

Does combat in D&D start with rolling initiative?

An old Crawford reply that Magic Missile hits you ignoring Mirror Image duplicates…

Can you dual wield hand crossbows or not in 5e?

Assuming I had conjured the mind first, if I’m inside an Otiluke’s Resilisent Sphere, can I still cast spells as if I was in the mind’s space?

Would a Warforged get detected by Detect Magic?

Is it possible for a Warlock to lose the support of a Patron? Switch patrons?