Adding in 6 pounds of food, thats about 50lb of gear. Not too bad for a first attempt at backpacking.
First off, get all the stuff in two paper(large sized) grocery bags. Then weigh each bag, roughly. This will give you the approximate volume and weight capacity of a pair of packs you will be looking for.
Second, take all the stuff to the store with you, but don't forget to leave some space for "food, fuel and water" or consumables. Try on every pack in the size range that fits the stuff. Don't forget, if you really like camping/hiking, you will be upgrading to lighter, smaller gear as you go.
Third, choose the most comfortable pack, in the lightest weight they have. Later, once you have more experience, you might want a lighter pack, or, smaller pack, or more versitile pack or less durable or something. Don't worry about duplication. I have a half doven packs I use regularly. 2 for solo trips, a couple for the wife and I, a couple loaners, and several others for special things (trail work, shelter maintenence, training, canoeing, etc.) The process of selection can take as long as a couple days, since it IS a process.
Fourth, it has to handle the weight. After all, that's one of the big reasons for having a pack, to carry your gear. Try every pack with the weight for *at least* a half hour. You cannot tell in less time than that without a lot of experience. First time through will take time to adjust everything, or, "dial it in."
Fifth, avoid packs over 3 pounds. Unless you are on an expedition to Mt. Everest, you do NOT need a huge and heavy pack. For two or three days, temper this with your intended destinations. Peaks and Mountains? Lakes and Rivers? Rolling hills? You don't want a 3lb pack going up a mountain. Nor a Mountain pack for stand up hiking and bushwhacking. Use your judgement, only you know your needs in that regard. I typically use a 8oz-14oz pac for most solo hikes up to about a week. I also use a 3#3 for two weeks or longer trips.
Sixth, chose one with as much dual purpose as you can get. A removeable side pouch makes a good bear bag for smelly items. A pad pocket lets you use a pad as part of the frame. This is more advanced, so, you *can* ignore this for now. REI or EMS does not carry these. Zpacks, GOssamerGear, SMD, others all do this to some degree but are more specialized.
Seventh, FIT, FIT and FIT. Everything about a pack is comfort. If it don't fit, don't get it. Same for your partner. You may end up with completely different packs. That is OK. After adjustments, it needs to fit like a glove. No pinches or weight pressure points. Even pressure on your back, shoulder harness and waist belt is what you are looking for. Your legs, knees and feet need to carry the additional weight. Make sure you are in shape to do that. Some people like external frames, some like internal frames, some no frame. Depends on you.
Eighth, I prefer three pockets, one for kitchen gear, one for water, one for ready stuff (trail bars, candy, water treatment, bug dope, tp, etc.) A waist pocket is handy for a camera.
Lots more to this but you should be able to find a light pack that will fit well for the gear you mention. Later, with a bit more knowledge of how, and why, and what you like, you can think of mail order. For now, stick with something you can return at one of the chain stores. Your confidence WILL increase as you do more hiking. As will your comfort as your gear declines, quantity, volume and weight.