GuitarHero and Rockband guitars will not work with guitarfreaks perfectly. By default, they are set to hold down the "left" button to recognize it as a guitar controller. Therefore, when you try to play guitarfreaks, it constantly scrolls through the menus and you can't stop it. Also, in older versions of guitar freaks, the keys 1,2, and 4 on a guitarhero or rockband controller constitute the Red green and blue buttons on Guitarfreaks by default, making it difficult to play. With versions of V2, Masterpiece Silver, Masterpiece Gold, and V3 you can remap the keys in game. Still though you have to deal with the menus, whereby you would have to unplug your guitar, plug in a dualshock, select your song, then plug the guitar back in before the song starts.. very annoying. Likewise, Guitarfreaks controllers will not work for Guitarhero or rockband because they only have three buttons. Drums wise, Guitarhero/Rockband drums will not work for Drummania by default, as there are only 4 pads, while drummania requires 5 to play. A drummania controller might work for rockband, although I am not familiar if whether they are programmed similiarly to the guitars, i.e having to have the "left" button held down to recognize the controller. If it is not as such, then a drummania controller could be used for rockband, as long as you can remap the controls in game.
Your best bet for starting guitarfreaks or drummania is to pick up a KOC (Konami Official Controller) these run for less than 100$, and you can sometimes also get a good deal on the forum marketplace. Also check
Buy Video Games for Consoles and PC - From Japan, Korea and other Regions! - Play-Asia.com.
If you want to play Guitarhero/Rockband, your just going to have to buy the basic peripherals for them, there really is no other alternative.
Good luck.