My line of thought would be to check which airline you would like to use future point earn on. e.g. if you wish to fly to Asia with Singapore Airlines, I would fly Virgin Sydney to Perth and credit points earned to Virgin Velocity. If you wish to fly Qantas or oneWorld airlines to USA for example, I would fly Qantas or Jetstar and credit any points earned to Qantas.
Another factor is whether the cost of flight is an issue. If you don’t care because work is paying for it, just stick to the airline you would prefer to earn points in. If you are choosing your flights based on costs, create both accounts and credit points to one or the other depending on which airline you fly with.
Credit card choice is much more complex and personal. PointHacks is not allowed to advise on credit card choice. General advice is similar to that above, pick what point earn you value then choose the credit card that gives you the most point earn for the same amount spent.