Do what feels right. Intimidate, yeah be on the wrong end of a dog your pretty sure is willing to eat you will prove this point, or try to give a house cat a bath! Most animals can communicate the I am willing to hurt you pretty well.
Impersonation for I am just a normal animal of my type seems appropriate. Please note people will react to you as appropriate keep in mind most people cant tell the difference between a wolf and a large dog at a glance. That being said alot of people are not comfortable around large dogs. Also a horse running around down town Seattle will attract alot of attention, same for any of the cat shifters since they are generally big cats. Foxes might get mistaken for medium dogs at a glance but most people can tell a fox is not a dog if they get a good look. Bird shifters will have the easiest time as they can fly around and sit or roof tops and such where most people wont notice them.
Con for I am friendly and want a pet/treat seems legit to me. Again none of my cats or dogs have ever had a problem communicating to me that they want food or attention.
Past that most social skills are probably not available for interacting with meta humans. Now if the shifter goes and hangs out with more animals sure why not, just keep it with in the limits of what animals understand unless hes dealing with another shifter and then meh I would just assume they can pretty much do the whole social thing with each other regardless of the form either shifter is in.
As for communication, yeah they cant talk. But if your team knows your a shifter you can probably work out some basic communication mechanisms ahead of time. Things like making the team know what going "On Point" looks like for you. If you dont know that "On Point" is look up hunting dogs I am sure they will have some you tube videos of it as hunting dogs, especially bird dogs have been trained on it for hundreds of years. Also basic I nod/tap my paw once for yes, twice for no etc. It would be very basic but they can get it done. Also you will have to decide if a shifter can use trodes or not. I would probably allow it as but the custom trodes would cost like 1k nuyen. It would be more for lets face it a wolf/tiger/ what ever animal they are has a radically different brain then a human so its gonna need different software to work and that's a very limited market. Oh the special animal trodes would not work in human form, they would need human set of trodes for that. But thats my opinion as I dont think cannon has anything on this subject.