Wow, look at you, 12 weeks already!!

I can't help you with the pram/travel system because I haven't seen it, but make sure you are really happy with the pram because it's awful if you are not! I have a P&T's that I recently purchased and I LOVE it!

Nothing at all wrong with the Safe N Sound Guardian, it will do the job just fine (you can use them from newborn to up to 4 years of age) and it exceeds the Australian safety standards so you know it will be safe.

A lot of people swear by the Angelcare monitor, I sell them easily second hand so they seem to be very popular. $149 is a great price, you could sell it again on eBay for up to $100 once you've finished with it so you'd get most of your money back (that's if you're into selling on eBay LOL - keep the box and instructions if you are )

The Mothers Choice highchair is a good price, but I also recommend the Ikea Antilop highchair over a hi/lo highchair! It's so cheap, but by far the best highchair I have used. The hi/lo ones get food stuck in all the crevices of the seat cover which make them really hard to clean. But if you ARE after a hi/lo highchair, the Mothers Choice one looks like it would do the job

Hopefully that kind of helps? I live and breathe baby products thanks to my business and talk to mums everyday about them!

Have fun