To keep the lighting consistant, take a frame with the person you want to mask, then take him out for the next frame, then put him back in and move him slightly, and keep doing that so that every other frame is the nonmasked background picture.

I don't get the second question. What do you mean, something like a minifig arm?

To anchor a set down, I use masking tape. Lots and lots of masking tape.

And the best way to make your own music? Download a free musicmaking program, such as MuseScore.

2. Have a program with onion skinning (animatordv simple+, Stopmotionpro, heliumfrog, ETC.)
3. tape it underneath (like double sided tape) it works extremely well
4. Use finale notepad or musescore (if you have a PC) Macs have garageband
1."bubble" and tape white paper around your lamp

Hopefully all this helps!

Tejas VIM Studios