pet stores are very stressful places for animal animal, but especially for rodents as they are seldom given enough space or a place to hide among other things. so if she was stressed and a strange rat was just tossed in with her without proper introduction procedures, its not surprising she would have attacked. given enough space and proper introduction procedures there is no reason to assume that she would be violent again.
it sounds like you are set for alice and i have nothing against that. i myself have gotten from pet stores in the past. i no longer do as it is frankly more convient to get from rescues. what i do suggest though is taking Everexanimate up on her offer of babies for playmates for alice. where you are just starting in the rat world you'll want some properly socialized rats to help bring alice out of her shell and for you to get the full experience of what a rat that was loved and cared for their entire lives up the point of adoption can actually be like instead of only get that love and care at the point of adoption. you may have some time getting alice to learn to like humans and trust them enough to be openly affectionate and generally just to be confident enough to be herself. most pet stores will get from mill breeders, but even the ones that take in litters from private people, being in a pet store for any great length of time can do things to their confidence and trust. pet store rats can become absolute heart rats, i'm not saying that they are a lost cause, all i'm saying is that as a general rule they take more time and patience to come into themselves. getting home raised and properly socialized rats will give you ready-made-family-rats. i'm not saying that they are more deserving of love over alice, every rat is equally deserving, but there will be less work in home-raised babies then with a pet store babe when it comes to their confidence issues.
as for other advice, always keep learning! your rats are going to teach you a lot, but only if you listen. other people's trials, and even their failures will teach you a lot, remember to learn from others. everyone is going to have an opinion and many will have different ways of doing things, there is no one right way. some things that work for their rats will not work for your rats. remember to try but to recognize when you have found something that works for you. having said that, there are still wrong things, don't endanger your rats because pine is cheaper or someone gave you a seed mix.
other then that the one most important piece of advice i can give you is to get a can and keep putting money in it. anything that you can spare, every piece of change, including those pennies that no one wants. vet bills are brutal and the worse feeling the world is not having enough to cure something simple like a mild URI and having to watch your babe getting worse and worse and worse until what started off as a simple to treat little illness kills them. simply because you didn't have the money at the right time. when you get that can don't spend any of it unless its for the vet. not for the cage, not for any toys or treats or even food, put money aside for that stuff separately. for this can it can ONLY be used for the vet and NEVER borrowed against. even when you have hundreds in there, keep putting in more. emergencies always happen when you are least prepared for it and always when the vet office is closed. sometimes you need to wake up YOUR vet, not any vet will do as rats are not cared for by all vets, and that can be very expensive. i cannot express enough how important that vet can can really be. i learned the hard way, i don't want anyone else have to go through that for something that is so preventable.
so i think that's all i can offer you right now. if you have specific questions i'm sure the forum will always be willing to help answer them. i hope i've been of help, sorry for being so long winded.
