These live Ebola vaccines are dangerous enough that formulating and filling the vaccine vials "may require that these processes take place in a Biological Safety Level 2 (BSL2) facility."
While the solicitation says multiple live Ebola vaccine types may be in play, only two are specified by name.
"1. RVSVdG eBOV vaccine replication-competent live virus vaccine utilizes a recombinant Vesicular Stomatitis Virus (rVSV) lacking the native VSV glycoprotein (ΔG) and bearing the glycoprotein (GP) of ZEBOV, which is the target of protective immunity. The rVSVΔG ZEBOV is an attenuated virus and capable of limited replication after administration, which is believed to be the basis for the potent immunogenicity of this vaccine vector.
2. rVSVN4CT1-Z-EboV Vaccine utilizes attenuated replication-competent rVSV vector that is injected IM, it undergoes limited propagation at the injection site and in the local draining lymph nodes, but does not spread to other organs and tissues."
Both of these vaccine use the Vesicular Stomatitis Virus as a delivery mechanism of Ebola proteins chosen to trigger the Human immune system. While not mentioned specifically in this solicitation, there is also a Live Ebola vaccine that uses a Live Rabies Virus as its delivery mechanism.
Unfortunately vaccine work is often pushed on the public as if it were settled science, unfortunately it often is more like well describe Alchemy and Voodoo. A key example being last year's live influenza vaccine which to scientists amazement offered no protection against last year's deadly H1N1 Epidemic. Its possible that that vaccine malfunction may have actually contributed to the pandemic.
CDC Statement on LAIV Effectiveness and Vaccination of Children