[@Benzaiten]
Just a few questions so I can wrap my head around the concept in action a bit better, if you don't mind.

1) Will you be playing a PC as well or will you just GM aka play NPCs (is Donnelley an NPC or PC)?
[i]Both.[/i]

2) How will an investigations be played out? 
- Will you be placing clues/evidence somehow withing the RP? As a kind of [Player: I investigate the closet | GM: You find EVIDENCE] [i]player action -> GM answer -> player reaction[/i] formula that many tabletop games use? 
[i]Yes, as a simplification. A lot of successful investigation depends on what your character is skilled in, and how skilled. Someone with a Computer Science of 80 will have better luck, and a higher chance of retrieving data from a hard drive without corrupting the information, than someone with a Computer Science skill of 60.[/i]

- Will dice be involved? If so, how dice-heavy is this supposed to be? (E.g. only combat is a quick die roll vs "roll a die to determine whether you can see anything through the muddy window")
[i]Again, yes for simplicity. The way dice come into the equation is if some variable in the situation is adding pressure to the character. Say, trying to shoot someone in combat, or defuse a bomb while the timer is counting down.

Otherwise, like above, it just depends on what skills your character has, and how skilled they are.[/i]

- Also, if dice should be involved, are we following a certain system? Perhaps the tabletop game Delta Green has a dice system?
[i]Delta Green does have a dice system, and we will be using it. It works off of a percentile system, so we’ll primarily be using d100s to determine success or failure.[/i]

- Is the investigation fully GM-driven (as in the GM decides the clues, evidence, bad guys, hurdles, etc.)? I'm assuming this might be easiest
[i]I provide the framework by supplying the plot and the basic problems to be solved by the PCs. It depends on PC problem solving what happens. It is player-driven to an extent. The world happens to the PCs as much as the PCs happen to the world, if that makes sense.[/i]

3) Should PCs be team members of years already or rather new recruits or anything goes?
- If new recruits are allowed/wanted: Should the PCs know anything about the 'occult' yet or are they supposed to be clueless in the beginning?
[i]PCs are assumed to have had a previous brush with the Unnatural. It is their deftness in handling the situation, and/or the ferocity with which they researched what exactly happened to them and what they saw that puts them on Delta Green’s radar.

The only reason you aren’t tied up like a loose end is because someone thinks you’re useful enough. This is to say that your PCs have not yet been “read on” to Delta Green and the conspiracy that keeps the knowledge of the Unnatural out of the public eye. Your character is a newb. An FNG. Still a competent professional, but they’ve never been in something like this before.[/i]

4) Can/Should the players also add to the occult lore of this world by creating their own (within the PCs backstory for example)?
[i]One of the main themes, Unnatural phenomena, and motifs of the RP that preceded this one was completely player-made. I decided to add it to the “lore” of my campaign. So, yes, players may show their creativity.[/i]

Sorry to spring all of those questions on you in a simple Interest Check ^^ Feel free to take your time answering them or to gesture me gently out the door xD
[i]Not at all, I’d love to see who you create in the coming days. Just be aware, I am a picky man. Bring your A-game. ;)[/i]