What is the motive of a miner to include transaction in a block? My question is divided into different parts :


Can a block include only coinbase transaction ?
Why should a miner wait \ include more transaction after starting to create a block ? 
If a miner stops the mining process for including new arrived transaction, does that makes him re calculate the previous nonce possibilities for creating the block ?
Blocks can contain whatever is valid, anything beyond that is up to the miner to decide. Including no transactions other than the coinbase transaction is valid, and there is no way of having a rule where this is not the case (was there transactions to include at that point in time?). Miners will absolutely not wait for transactions to be available to mine, as their main source of income is the block reward. 
Miners are incentivized to include transactions by the creator of the transaction paying a fee, and the miner collecting it. Including no transactions mean they miss out on income. 
Mining is progress free, each attempt is completely unique and has the same chance of winning no matter how many you have made previously or what the contents of those attempts were. Inclusion or exclusion of transactions has zero effect on the chance of a block winning or not as the header is exactly the same length for each and every attempt.