First suggestion, which you most likely have considered already but tis worth mentioning... make a mock up out of some cheap fabric that is similar to what the finished linen will be...the last thing you wish to do is experiment with the good fabric and cut it right away...make sure you have a working pattern that fits first....
As to the sleeve...without seeing a picture, one can only assume that the cuff/facing is yellow? Is there a illustration of said coat so one can try and determine how the cuff is cut?
And regarding the felt... what do you mean by felt? As over here, the first time of felt that usually jumps to mind is the kind used in crafts, which I am not too sure would be the best item for the interlining of a coat...I would highly suggest a linen canvas which was often used in coats of the period.