I believe the 3 anagrammatical solutions are:
IRONSIDE, DERISION and RESINOID
In all, I am a soldier,
My prefix can be found on a plane,
My suffix is at the edge,
My infix is an island, in Spain.
In all: An 'IRONSIDE' was a nickname for a Puritan soldier fighting for Oliver Cromwell in the English Civil War.
Prefix: IR stands for "Instrument rating" - qualifications that must be held by a pilot before they are permitted to fly an aeroplane;
Infix: ONS is an island in Galicia, Spain;
Suffix: The SIDE of an object is 'at the edge'. (Or even something that is ONSIDE might be 'at the edge'...)
NB OP revealed in comments that their intended prefix here was actually IRON, being the name of the steel blade on a carpenter's plane tool...
In all, I am a mockery,
My suffix comes with a charge,
My prefix was a Sumerian city,
My infix, a dwarf that is large.
In all: DERISION is a synonym for 'mockery'.
Prefix: DER was a Sumerian city;
Infix: ERIS is a dwarf planet, but one of the largest known to us;
Suffix: An ION is a charged particle.
My prefix is what it's about,
My infix, an evil act,
My suffix tried to stop pizza,
In all, I am just an extract.
In all: A RESINOID can be a gum resin extracted from plants.
Prefix: 'RE' in the subject line of an e-mail tells you what it's about;
Infix: A SIN is an evil act;
Suffix: The NOID was a character used in advertising for Domino's Pizza who would try and sabotage the pizza-making process ('stop pizza').