B I have a standard collection of DIY tools. The main additions for aquaponics have been a ‘hole saw’ set. Indispensable for joining pipes to tanks etc. The other was an angle grinder. Used this to chop up the IBC. I bought a cheap one but it did the job. I could have hired but I don’t think the difference was worth worrying about.
C Water. Probably the key component of any aquaponics system. Most people will have two sources. Rain water and tap water. If you are going to use rainwater then you need to think about some sort of harvesting system and storage. It could be a simple water butt connected to a downspout or as elaborate as you choose.
D Just finishing up the construction of the NFT tubes. I had a, DOH moment!