OK, being an RTF the CG is probably correct. if it is shown anywhere you can just verify it or have your instructor verify that it is in a good "generic " location. He will know where it belongs if he has been flying very long, and that is how you get to be an instructor at a club usually.

Battery is also probably OK. I had forgotten this was ALPHA RTF when I wrote previous. Remember for future planes though.

It is OK for end to "flop" in the air, much better than doubling it back or tying it or cutting it. Does it look like picture on box/manual? Should be fine.

I just went thru the manual and you are correct in that they fail to mention rubber band count. This may be considered a failing in the manual.

Charge batteries and you should be good to go. Did you get enough rubber bands