I agree with Biggie. Park them while you're looking into ways of setting up content websites, then you should already have a first idea of how much traffic the domains receive without being developed.
But to be honest, I doubt you have 100% quality domains if those are 5,000 newly registered domain names. The reason being that it is relatively difficult to find such a great number of valuable domains still available for registration. In addition, making a profit off those domains should turn out to be easier said than done, too, because of the size of your portfolio. It requires quite some time and work to quickly flip domains, which is what you're going to do; even more so if you want to flip as much as 5,000 domain names.
I'd say get another opinion on your portfolio. I sure hope you hold good domains, but they might turn out to be of lower quality than you initially thought. In that case, it's important to get rid of the bad domains and not to bemoan the sunk costs.
If the domains are in fact good, parking them is a good way to start. You can then still look for a partner for development, hire somebody to create unique content and have somebody design the templates for your websites.
