If you are a child , and are having problems with an adult on the internet , perhaps it’s you that should phone the police or at least tell your parents ? Rather than go on another forum and cause more drama ?
a genuine and new Vortex crossfire red dot is around £160 with a complete no quibble lifetime warranty , or pick one up secondhand for £100 ish and still have the lifetime warranty .
Battery will need to go in the stock tube with whatever Magpul stock you decide on , unless you get creative and start modifying things .
a standard MOE grip will not fit , due to the motor arrangement and fixing points , you’d be better off with an AEG specific PTS grip .