3D Virtual Event Platform (Web-Based) -- 2

Hello, I would like a 3D Virtual Event Platform (Web-Based), where I can host different types of events/fairs, so everything should be customizable. We have a designer, that he will do all the 3D content, I'm looking for a programmer (PHP, Unity or other) to do the programming side of course. It will be a virtual location (Like the outside of a Convention Center). With signs outside of the event, sponsors area, etc. People can register to each event, they can create their profile with their contact info, and enter to the virtual event. People can walk virtually through the different halls where they will see the virtual stands/booths. Each stand should be customizable with colors, logos, pictures, information of company on that stand, videos, pdf files (brochures, catalogs, etc). Attendees looking for different options, can see more info on each stand, like the name, location, options they offer, download digital brochure, catalog, etc, and they could fill a quick form requesting more info. A live chat and call on each stand in case they need to ask questions in real time. A conference room inside the place, where attendees can see and hear a presentation made by one specific speaker (speaker will share their powerpoint presentation on the screen of the virtual conference room). An agenda of all presentation can be found outside the conference room, with a calendar outside the room with the info of all the presentations that will be going all day. for example, 2:00 pm X university, 3:00 pm Y University, 4:00 pm Z University, etc. To give you an idea, we would like something similar to what you can see on these videos. Example Video #1: [login to view URL] Example Video #2: [login to view URL] Example Video #3: [login to view URL] If you have any questions please let me know. My questions: 1) Will you be able to do it? 2) Cost? 3) Time? Thank you in advance.