Pre & Post BW 7.0 to BW 7.3 Upgrade Activities with respect to BW stuffs

Hi Experts,

                   We are going to upgrade our BW system from BI 7.0 EHP2  to BW  731 EHP1. So could you please guide in the following

--1) what are the points/steps we have to do before upgrade to BW7.3 and after upgrade to BW7.3 ?

--2)  Do we need to migrate our existing BI 7.0 objects(like Cube,DS,DSOs,MP etc) after upgrade to BW 7.3  ? Anything manually we need to do here ?

--3) Do we need to migrate our bex query to BW 7.3 ?

--4) We are using ZAnalysis_Pattern as a WAD template( just copied from 0Analysis_Pattern and then customized for our portal formating) for executing report in our specific format in Portal , in this case do we need to do follow any steps either before BW7.3 upgrade or Post upgrade ?

your suggestions and  comments will be appreciable ...

Thanks,

Surajit