Hello, and welcome to APUG.
Any lens is a portrait lens...it just depends on what kind of portrait you want. One of my favorites for portraits is a lens that is about 15% wider than a normal lens (35mm on 135 format). Another of my favorites is one that is nearly 200% longer than normal (135mm on 135 format). Also, you can do a great deal with a normal lens, and that is an understatement to say the least; It could be all you ever need. Personally, I would start with an 80 and a 250, but that is me, for the way that I shoot. If not enough budget, I'd just get the 80 for now, as it will be the most versatile.
Yes, I use a light meter. However, we can't suggest one until we know whether you need it to measure flash or not.
IMO, no reason to pay any extra for a camera that has TTL flash metering capability, especially for in-studio portraits in which you will be using a hand-held meter anyhow. In-camera meters of any type are always a compromise to a hand held light meter. Even if your camera measures flash, it is still measuring it using a rough, generalized pattern and a reflected light reading as opposed to an incident one. In this case, I would choose a camera based on condition.