Amanda, check with the Tradewind liners. You will see all the components detailed on their website and the purpose of each component. They are great about answering questions also. I bought all of my components from them . They have excellent products and great prices. I have a 54" hood liner, inline silencer, 1400 cfm external remote blower on my back roof. The equipment is very quiet and very efficient. Much is made on this forum about Brand names but my vent system is much more for much less than anything you will see written up here. Hope this helps you with your decision. You can e-mail me through GW, Here is a link to the company. Here is a link that might be useful: Tradewind Hood liners

No, there's no saftey risk to not venting to the outside but if you have the option to vent out then that's what you should do. Recirculating hoods are better than nothing but you really want to vent the smoke, grease, heat, steam and odors to the outside and not recirculate them in your kitchen. There are dampers you can put on the vent pipe to prevent cold air from entering your kitchen.

Going straight up would be a little more effective but, yes you can make a 90 degree turn. Each 90 turn is equivalent to adding xxx feet of ducting but that shouldn't be a real problem with a powerful hood.

Heh! Yes, mattress is a very good example. This is why ca. 2007 I started reading up on kitchen ventilation so I could ignore the magic that was being asserted and determine for myself what was needed. In a hood, most of the effectiveness is embedded in the sheetmetal shapes and the blower motor and fan. I rarely hear of fan failures (I can only recall one on this forum). Broan absorbed NuTone that used to provide a lifetime guarantee. Wolf uses Broan. If the hood exterior is non-magnetic stainless steel, it shouldn't ever rust or develop surface staining. What tends to fail in lower quality hoods are fan and light switches. These hoods may have thinner sheet metal, but that is not a point of failure. It might have a relationship with rattles. Mean time to failure with electronics will typically decrease with increased parts count. So some risk of shorter lifetime may be present where fancy motor control circuits are in use. It is fine to go shopping and look at hoods from the point of view of ease of use or lighting or construction quality, or aesthetics of design, but nothing should be purchased until you have gone through the process of understanding what you need a hood system to do and what its parameters have to be to achieve it. Since modern higher performance residential hoods for pro-style cooking equipment derive their requirements from commercial cooking ventilation, you may wish to start by downloading and reading the first dozen or so pages of the Greenheck Guide: https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf