newbie to sport and BT website questions??

somewhat experienced person here -- will give you what I think is the answer most will give you ---

1) Generally you try to seperate your workouts to different parts of the day -- as you get closer to an event you are training for you will try to do "brick" workouts which are usually Bike/Run workouts together to simulate the tri and give your legs the feel of running after biking

2) I believe most people would tell you to always have atleast 1 rest day a week -- no matter what phase of training you are in -- one complete rest day is usually your best bet.   So if you can combine 2 workouts into one day and give yourself a rest day -- its probably a good option.  Also since you said you are new to this and I'm assuming new to training still in multiple sports -- the first phase is just about adding volume and adding workouts in all three sports.  So your first phase (a prep/base phase) is low intensity volume adding workouts to get your body used to the volume and a general rule of thumb is not to increase your workout volume by more than 10% each week --- it should be a slow buildup at first to get adjusted and give yourself a big fitness base.   (your starting point though all depends on your initial fitness level ofcourse)