You're not going to be able to take statistical data on four teams with one person.
What I'd suggest:
- Do a bit more pit recon than normally makes sense. Pictures, what the robot theoretically does, etc. etc. Ask about stuff that you normally wouldn't in pit recon. Everyone lies a little about their own performance, but you don't have the manpower to collect some of it yourself.
- Subjective stand scouting of teams may be doable. Stuff like "scoring speed", "robot speed", "ball collection", etc. that you want in a partner? Instead of bean-counting, put scales from 1-10 and subjectively rank each robot's performance in that category. This is not impossible to do for more than one machine at a time.
-If you need any help, see if other nearby teams have the resources to assist you, or possibly if you ask very nicely, data to lend you. My old team, the Conserve Steelers (I don't know their number), is a good place to start.
Best of luck!