umrah questions

As-salaam-u-alaikum. we are insha allah going for umrah in two weeks time and have these few questions.
Tawaaf
does one have to make istilam every time ie the 8th time after the 2 rakaats of tawaaf.
Safa Saee. does one have to complete the 7 rounds continuosly or can one rest if a person is tired.2] do you have to have wuzu when doing safa saee 3] i have a weak bladder and if i have to go to toilet does the round break and do i have to start all over again.