As a franchise attorney , this is a bit out of my area of expertise - helping companies franchise a business concept and advising individuals, as a franchise expert, on making franchise investments. However, I can say the following.
Expect nothing but legal trouble if you take intellectual property belonging to someone else and use it selling your stickers and decals. You need licensing rights from the owners of this intellectual property or they're attorneys will be all over you.
Kevin B. Murphy, B.S., M.B.A., J.D.
Attorney at Law & Franchise Expert
Director of Operations - Mr. Franchise
FRANCHISE FOUNDATIONS APC
To keep it to the basics; you are not allowed to sell stickers with trademarks or copyright material unless you have the owners permission (a license). There are specific rules for each, Ttrademark involves a "likelihood of confusion" where if your stickers look like something the trademark owner would be selling, sponsoring, or be associated with) then you are likely infringing the mark owners rights. Copyright has a substantial similarity test, if your work is substantially similar to work copyrightten (for example, where it is obviously a copy) then you are likely infringing the copyrights.
The characters you mentioned are protected images and you would need a license to sell (or even give away) stickers with those images on them. A silhouette of an Album is okay as long as it is not obviously a particular album (a circle is fine, but a circle with "Abbey Road" on a label on it is not.
If you are serious about getting into the sticker market, I suggest you consult with an attorney in your area.
Either stick with art you create or obtain licenses.
My disclaimer is simply that Avvo already has an adequate disclaimer.
One way to circumvent the problems of copyright infringement, licensing rights, and trademark infringement is to research what images, logos, music, etc are in the public domain and no longer subject to copyright protection. Images from before 1923 are generally considered public domain. You can search the Library of Congress for high resolution images. This might help for historical figures, presidents, major events, etc.
The Beatles or Batman on the other hand are more contemporary, and would likely have a legal right to prevent you from duplicating and profiting from their image(s). However, you may always seek out the rights holder and request permission to use their image/trademark, and include in your offer the fact that you will be generating publicity and exposure for them and you will only use their image/trademark in ways they approve of.
Good Luck in your Business Ventures!
This answer does not constitute a legal consultation, or definitive answer, nor does it establish a lawyer client relationship. Each case, controversy, or situation is factually different and requires particularized evaluation.