Hi Frank and welcome to the forum.
Firstly, I should point out that this is primarily a customer to customer forum. Some DreamHost staff do post here on a semi-regular basis, but this is not the best place to ask questions directly of DreamHost, for that I suggest you use the contact form linked below;
Having said this, I will try to answer your questions as best I can.
To be honest, I don't really think any shared hosting arrangment is suitable for your site. Perhaps you should be looking at purchasing some kind of dedicated server for your site.
DreamHost no longer has a hard limit on CPU usage. Basically, unless your site is using enough resources to affect other customers on your shared host then you should be OK. However, it does sound like your particular site will likely cause problems for other customers on your server, if not immediately, then perhaps as it grows.
The RAM in each server varies, but I can tell you that my particular server has 3GB.
By the way, you refer to the level 3 plan as a 'Reseller host plan', this is not strictly correct. DreamHost does not sell a plan specifically for re-sellers, but they do not restrict customers from re-selling any of their plans.
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