Wow first let me welcome you to RCU. OK I am going to answer your two direct questions shortly.

But first since you posted these questions in the beginners forum and as you noted are a beginner to RC flight, you need to understand that Real turbine engines no matter how small are a disaster just waiting to happen and to consider attempting to fly one with no formal help and without learning to fly proficiently first is a going to result in a flaming hole in the ground somewhere. Even very proficient gas or electric propeller pilots have issues often on making the transition that no other type of type of propulsion presents.

Now not knowing what country you are in be aware that in the US if you fly a turbine at an AMA field you will have to have a 'turbine waiver' This requires a minimum number of flights and an actual flight test signed off by two turbine waiver pilots of which one must also hold a Contest Directors certificate.

Now to your questions and yes a test stand can be useful in learning a new type of turbine or operationg procedure. Here is a picture of one I was using just last weekend to learn the use of propane start procedures since my three other engines are kero start, procedures are very different.
For a test stand and the one in this picture is the Dubro fifty ounce with the gasoline plug as well as gas safe clunk line. This is a reasonable size for you stand and is reasonable in size for the snaller engines.

Question #1

Yes you can use a variety of tanks however the stoppers and clunk line materials must be gasoline, diesel, kerosene and Jet A safe. Yes those fuels can all be used but only for certain engines and with certain parameter changes on your GSU (ground support unit) see your manual.

Question #2

The BVM UAT that you ordered will have an appropriately sized pickup tube and fittings. Another popular UAT and less expensive is the one shown in the picture. It is the Hansen UAT.

Its hard to tell but you sound like you may be designing your own jet before evening learning how to fly and this is an even worse idea.

John