Remember, the comments are only opinions. Read all of them and weigh them carefully. Lifeguard Systems is a great training institute and can help you on equipment and purchasing.
We just set a 40 member regional team up 2 years ago.
Let me start with the tanks. While I use HP100cu/ft tanks recreationally, we only use 80cu/ft al for public safety. First if you need to bail out you can ditch your weights. If you have a HP tank to cut down on weight, you are no wearing it and cannot ditch it. Second, in PS diving you should limit your divers to 20 min dives. You don't need the extra volume. A 19cu al pony is plenty to bail out. If a diver gets entangled the back up diver should be bringing a contingency bottle to them. We use the pony tamer for connection.
We have the Whites Fusion dry suits. They have a lot of flexibility in them, but it's like wearing a trash bag. I would recommend the Ursuit.
We have 40 Guardian masks and they work great. We use the wireless Buddy Phone system and have no problems with it, except for remembering to put in new batteries. As for an extra mask, PS diving will teach you to breath without your FFM on. You will learn to don and doff it under water and come up on your pony. Certainly there is nothing wrong with carrying an extra mask with you but it isn't necessary.
For regs, keep it simple. We have Sherwood regs. Easy to repair and cheap to replace.
When getting fins, keep in mind you need big enough fin pockets to hold whatever drysuit configuration you use. With the Whites we have to wear boots which requires a large fin pocket.
Some things to remember when setting your team up. Besides diving equipment you will need, harnesses, some sort of pony reg restrainer, Line bags for tender to divers as well as back ups, a way for the back up diver to connect to the primary divers line in case of emergency, ankle weights for those who want them, pop up canopies to keep divers out of the elements, chairs for back up divers to rest while waiting, weight belt harnesses for those who have no ass, a contingency bottle with first and second stage that has it's own carrying harnesses and dozens of locking carabiners.
It is real important that whatever money you get for the team includes continual training (we do 12 drills per year), maintenance of all the gear and recertification classes. Also while in an ideal society you would require the divers to attend all the drills, the reality is if you require 80% of them you are doing ok. Every dive is training, whether it's recreational or organized. Be sure your divers keep diving outside of the department.
If I forgot anything I apologize.
Mike