If I start a clan, does that exclude me from joining another

A
Create it and if doesn't work out, pass leadership to a smurf so you don't loose the 1500.

To pass on leadership, promote your smurf twice and on the second promotion it becomes leader. Then you become an officer, and you can leave the clan to join another. This is done from clan menu, leave clan.

B
If you lead a clan, and then leave you can join another one. There are no restrictions.

C (if I remember well)
There is no disband clan option. The clan is disbanded when the last member leaves. So, when you are leader there are two cases:
C.1. You are the only member, thus it's disbanded upon your leaving
C.2. You pass on leadership, and then leave.

D
There is no refund for the 1500

E
You can't hop from one clan to another, first you must leave the one you are in and then join another. On this topic, if you join or create a clan, the invites you have received are still valid and are not cancelled until the sender cancels them.

This is done, so you still have options in case the one you join doesn't work out, i.e. you find out they are tankers and leave the same day.

This won't help you much though, since to discover if the clan was worth it takes usually quite a while thus the current invites will be probably cancelled in the meantime.