Almost...but not quite. The endowment is received as restricted income. Depending on if the restriction is permanently or temporary you would need to classify as such. Permanently restricted donations cannot be spent. Temporary restricted donations can be spent provided you spend them on the named restricted expenses. If temporary and you spend them, you move them from temporary restricted to unrestricted and adjust your equity accounts accordingly.
As for investing, you just move money from one bank account to another. Any earnings would likely be unrestricted interest income.
QuickBooks does not provide proper financial statements for NFPs. When working with NFPs, I usually needed to export to Excel. Any temporarily restricted assets that were released from restriction show up as a negative income item with the same amount shown in unrestricted income.