Apparently the said transaction is permissible, and it is not considered to be prohibited gambling. The deal here is merely selling a ticket for a low price with the condition that if the chosen numbers match the company's randomly selected numbers the participant wins the prize. One becomes deserving of the prize due to fulfilling a condition included in the sale deal, so it is permissible to claim the prize. It is not obligatory to spend the money in the way intended, although it is better to do so.
If the semen was released, then ghusl must be performed before offering the prayers. The release of another fluid, such as what may be released during foreplay and sexual urges does not obligate ghusl.
Yes, the separation of water from the najis object is a condition in the process of purification if the water used is little (qaleel). This ruling is the same for all parts of the body, including the penis. If the najasah is urine then one needs to wash the najis object twice when qaleel water is used.
