The fact it's a Monday plays very much into this, as it's not a Magic Morning, so there won't be a pre-existing line for FP. (On our recent trip, I was lined up for FP for ST at 7:45 or so each MM day, and I had lots of company.)
If you are in the very first group of people, I would consider riding standby first, which should take about 20 minutes, and then getting FP. You should get a decent return time, and have a shot at a second FP at a reasonable time (so as to not foul up your other FP gathering). That's really the only way to get three rides in one day, without waiting a whole bunch in line.
Conversely, if you are at all buried in the pack, OR if you'd be fine with two rides, I would get FP right away, then get in line. If you get FP in the first 15 minutes or so, you'll have a return time within an hour, and still have a very good shot at a second FP.
There is one other strategy... if one of the party is a bit quicker than the other and knows how to use the Fastpass machines, you might consider having them walk a bit faster and a bit more aggressively and go get FP for both, and have the other person get in the standby line. IMHO people aren't all that obnoxious if one person is joining someone in line, and the queue area is mostly outside Star Tours. This strategy will not work if there is a line for FP and the standby line goes too quickly, but it has worked for us in the past (but in that case, we were a group of five, sent one person ahead, had four in standby, and the person who went ahead really, really booked!)