I have just noted that William Wallace's birthplace in Ayrshire - Ellerslie is only 1 Km or 1/2 mile from Annanhill (Caldwell of Annanhill). I don't know if there were any Caldwell's at Annanhill at the time of Wallace's birth but if there were they would have been next-door neighbours.
There seems to be some discussion as to whether Wallace was born at this place near Kilmarnock or at Elderslie near Paisley. From the web it seems that the general current consensus is the Kilmarnock property.
I also note that both the Wallace's and the Caldwell's had property in the same areas of Renfrew and around Kilmarnock and even near Ayr.
I haven't seen anything in any writings about Wallace that would suggest a Caldwell as one of his loyal supporters. Perhaps some diligent scholar might be abe to find out if he had a faithful Caldwell gillie.
The success of the Caldwell family in the following century would seem to suggest that they had the favour of either or all of the Wallace family (who only had influence through Wallace himself) the Bruce family or the Stewarts.
I cannot make anything of the Annanhill connection to Ellerslie or even that of Toddriggs nearby but thought it important enough to be worth a mention. Its currently in the category of interesting trivia.
I have found Toddriggs on an 1815 map - it is near Earlston on Toddriggs Burn. It is marked on modern maps as "kennels".
I seem to recollect from some of my researches years ago that there was an Orr family of Annanhill. Perhaps they took over from the Caldwell's.