Q1: Yes it is, but for the amount of effort you would have to put in, I would question whether you really want to do this. Google low-cost conveyancer and get a quote from one. Look carefully at the small print - they tend to add extras on if you want, say, less than 7 days between exchange and completion. I have just used one of these to sell an executor property at just over £300k. Legals fees were £149 plus, ID check fee, plus electronic transfer of funds fee-whole lot including VAT came to about £220. The LOWEST cost I could get from any high street solicitor - and I rang a dozen in various parts of the country - was £500 for the same thing. People have got to realise that solicitors still make a lot of money from these relatively simple transactions.
Q2: HIPs. The Government website says you need a HIP before you start marketing the property. If you have not marketed the property then it is my understanding that you do not need a HIP. If you find you do - shop around - paid about £160 for mine.