The effect of “Elemental Mistress Doriado” is even applied while she’s in your hand or Graveyard. So you can discard her for the effect of “Abyss Soldier”. Or remove her from play while in the Graveyard to Special Summon “Gigantes”.
You can activate “Fuh-Rin-Ka-Zan” if “Elemental Mistress Doriado” is on the field (no other monsters are required).
“Elemental Burst” requires 4 Tributes. “Elemental Mistress Doriado” can be used as 1 of the 4, but you will still need to Tribute 3 other monsters of the appropriate Attributes.
If “Scroll of Bewitchment” or “DNA Transplant” changes the Attribute of “Elemental Mistress Doriado”, her Attribute becomes that Attribute only. (Her effect is not applied.)
If destroyed in battle by “Dark Ruler Ha Des”, the effect of “Elemental Mistress Doriado” in the Graveyard is NOT negated because it is a condition as well as an effect.