It would be easier to start and finish the transaction in one method (or rather one request to a BO).

Why not send the request to BO containing a list of UPDATES to perform and BO would automatically wrap them in a transaction, returning either a success or error and the position of failed UPDATE statement? Even better send list of some struct and construct statements in BO.

While workarounds are possible (1 Job for BO + indefinite timeout + FIFO on caller part) it would probably be a bad idea.

1: How can the httprequest object be viewed in Ensemble?

You can use DEBUG=2, to see the output you need to start your BH in Debugging mode.

Another option would be to install Debugging proxy such as Fiddler and specify ProxyServer/ProxyPort settings in your BH.

Finally, you can install packer sniffer such as WireShark and see the raw packets.

These options are discussed more in detail in my series of articles Debugging Web: part1, part2.

2: How is the Adapter password set?

No need to write code for that, just set Credentials setting in your BH.