CDG player or software: unless you like swapping discs, a computer based system is best. Sax n Doty’s player is kinda low end. I like Karma, but did have to pay for it. Try not to wear out the applause button.
CDGs: online suppliers, ebay, craigslist, etc. For an idea whether the song you’re after is available: icroons.com.
Mics: go wired, XLR type, not built into mic. Samson not bad for cheap, Shure Elvis style for looks, SM58 for solid all around choice.
Mixer: smallest Behringer Xenix unit a good start, has effects built in.
Interface: USB sound card or USB to RCA phono plug interface.
Amp/speakers: Keyboard/PA amps typically have RCA phono plug ins for plugging an ipod in. Powered monitors also a good choice.
Effects: lots of choices. Some mixers and amps will have them built in. Digitech units have expression pedal. For unplugged reverb, sing into a drum.
Software tools: ripping, burning, copying, zipping, file renaming, file creation, songbook creation, lots of help out there.