I have one account that I made roughly four days ago on one IP, the same IP address I used to make a 20 month old account that I just recently logged back into. My friend lent me one of his shell accounts (which is 6 years old) that I have since logged into using the same IP, but obviously wasn't created with it.
My question is: I know I'm at risk for the first two accounts being iced as they were created with the same IP, but if I start logging into the 6 year old account using only a proxy, will it be in danger when I start ABing? Would it be a bad idea to AB with my main (which will be the 6 year old account) or should I only use side accounts? If I used those side accounts to AB with a proxy, and used my main with my real IP address, would I still be at a high risk for chain freezing due to the fact that I created the first two with that IP address?
I haven't started ABing or anything and I'm not planning on SSing at all. Sorry for all the questions, wasn't sure where else to put them and I don't want to muck this up. 
No body knows for sure how stringent TNT are with IP bans and chain ices, so I cannot guarantee that the 6 year account that you logged into once will not be involved in a chain freeze or be associated with your other accounts, but from my experience and in my opinion I find it highly unlikley that from that one log in, the account would be associated in the long run, especially if you continue to use a proxy on it from now on.
If you choose to AB on the accounts you created yourself you run a higher risk as they can both be frozen, I would Ab on this new shell and your other two accounts should be fine

Hope this helps!
I have difficulty finding a web proxy that supports some pages of neopets such as pet creation or some other event
can anyone help
There are some proxies that do this, but also some that dont, i'm not 100% sure what causes this to happen but 75% of proxies that are of a decent speed I find should be fine on all pages of neopets. I'm afraid its just trial and error! If you want a hand with finding some just PM me a rough idea of where you are located in the world and I'll try and help out