(1) UA1(1000) is on conversation with UA2(1005) ?

yes this possible

if you enable accounting you can view them in CDR

(2) UA1(1000) is on conversation with UA2(1005), then UA1 transfer to UA(1006)?

SER is a proxy, so to transfer to make conference you need to have

thirdparty software to make them in 3way call.

still those records also you can view them in CDR as for as i know

ram