Math Undergrad Wants to do Master's of Statistics
The good news is that it almost doesn't matter which path you take; you've got sufficient drive and determination, and from your observations about yourself, skill.

You're clearly interested in getting out there and working, which is great. Just remember that the work will always be there (for decades and decades to come), and that your time at school will be finite; try to enjoy it. :) 

To that end, I believe Option 2 is a really good option for you, and is the least risky option. TA-ships are fantastic, and if you can score one while being in school, it really helps cut down on financial pressure. Additionally, you're giving yourself time to really develop your own stats knowledge which will help you in either corporate or research environments. Even if your stats department isn't that great, your research is what you make of it; plenty of awesome people have graduated from non-elite universities and have since done amazing things, and it's not unusual to seek a little guidance or insight from people outside your department. Besides, if you're as talented as you sound, being a shining star in a department has its advantages. ;)

Getting to your Question 1, if you finish your Bachelor's while taking extra stats coursework, and then enter the workforce, that's fine, but it then becomes harder to reenter grad school due to various other real-life factors such as having to fully support yourself, possibly getting married (and/or having a kid) which may bind you to some location, and so forth.

Also, maybe your prospective job after Bachelor's will pay for your education, but going to school under those circumstances takes a bit longer, and it also means the school will have to be close to your job (unless it's an online program or whatever). It's just too easy for complications to creep in once you step foot out of school.