The best I can say is that there is something DESPERATELY wrong with you installation medium.
The mint installer is EXACTLY the same as the Ubuntu installer therefore if you have used Ubuntu before then installing Mint is no different.
The first was that I already have Windows 7 installed and there seemed no method of resizing the current parition easily to install it alongside
Although I have never in my life used the 'alongside' option I can assure you that there is a slider to allocate the amount of space you want for each installation.
Secondly once selecting the alongside windows option the installer just went ahead and started copying files
Well like I already said, I have never used this option. but imho such behaviour is precisely what most newbies would want.
Lastly (current problem) is that during install it asked for a username and password
No it doesn't. It asks you to CREATE a username and password of your choosing, that is all. How are you going to log in otherwise?
This post is so perplexing that I doubt I have answered your questions, but your assumption that there is something wrong with the Mint installer is just wrong, it works exactly the same way that Ubuntu does, and has been made as simple as it is possible to make it - too simple imho.
Fujitsu Lifebook AH532. Intel i5 processor, 6Gb ram, Intel HD3000 graphics, Intel Audio/wifi. Realtek RTL8111/8168B Ethernet.Lubuntu 13.10,Ubuntu12.10 (Unity), Mint16 (Cinnamon), Manjaro (Xfce).