I'll try to answer these to the best of my abilities.
1. Theoretically speaking, a task force currently has 59 members playing. Now, that's within current structure and assuming only one active zeus operator.
Here is a nice breakdown, under the Task Force Structure and Organization Tab.
2. Task forces are on a bi-weekly basis, however, there is always 1-2 operations per weekend. This means that although you only have two operations with your element per month, you can play a lot more than just those two days. Squad trainings are once per week, and platoon trainings are once per month, bringing total required attendance to 7 days a month, although, like I said, official events are running near daily with operations every weekend.
3. As far as I'm aware, no, but I'm not S-4. Someone please correct me if I'm wrong.
4. While this isn't disallowed, and is something I personally do, I highly advise against this for new members. You have to follow requirments to a T, and any minor error renders the entire loadout unusable. I'd recommend making them in your Recruit class with your instructor there's an entire hunk of the class dedicated to this. Loadouts are strictly controlled in operations, and no full arsenals are provided.
