First, they best way to avoid lines is ARRIVE EARLY, at least 30 minutes before park opening. I would recommend heading to Frozen immediately, especially on a Saturday. Then, if you have a small party, head to Test Track use the single rider line. With the addition of the 3rd theater wait times at Soarin are a little more manageable than in the past. You can probably get through all 3 of the BIG rides by 11am at the latest and then enjoy the F&G Festival for the remainder of the day. FP+ on the day of arrival for a Saturday in May will most likely be VERY limited, although I'll bet Soarin & TT would have some availability later in the day.
The absolute KEY to it all is ARRIVE EARLY!!
Have fun!