You can have dwarf elliptical galaxies.
Yes
Elliptical galaxies are large blob shaped galaxies that most galaxies will eventually look like. Elliptical galaxies are what happens when two or more large galaxies collide and coalesce.
yes they do
Both - all galaxies contain young and old stars.
Older stars
I think elliptical galaxies are the galaxies you are referring to. Scientist normally describe them as a flatted disk shape. These galaxies contain mainly older stars.
spiral galaxies (ours), irregular galaxies, and elliptical galaxies.
By virtue of their name, dwarf galaxies are smaller. Most galaxies are dwarf galaxies.
Spiral and Elliptical
While spiral galaxies are bright, elliptical galaxies are dim. Spiral galaxies are hotbeds of star formation, but elliptical galaxies aren't nearly as prolific because they contain less gas and dust, which means fewer new (and brighter) stars are born
Elliptical galaxies are generally old but not very bright