It is understandable when one sees something that is too tight to offer this advice, but in reality, there is no extra fabric available to let out.Most manufactured suits have 1/4" or 1cm seam allowances. Better to try a size up or a different style, brand or cut.Trousers at CB are really the only part of the suit with an allowance to let out.
If the holes already exist, then shortening at the hem will likely leave you with an odd situation with holes too close to the new hem.Shortening from the top that much especially in a patterned fabric is likely to throw off any pattern matching of sleeve to body, and may not be successfult to size the new sleeve position to existing armhole size.Try to find a jacket with non functioning sleeve buttonholes is a better way to go.
No you don't need to take anything out of the waist. I cannot see why you would think that because it is too tight. Try a size up if possible and compare.It is too bad that the generally the cut of trousers these days is so terrible. I don't know if going bigger will improve them, maybe, but I think it is the base pattern being used that is way off, and this is prevalent across many brands.
Well, I wonder what the back looks like.If the back is sitting perfectly, then the fix is to drop the neck point thereby adding length, but it is unlikely that there will be enough seam allowance left in a finished jacket to do so.
They do not seem excessive. The shoulder divot is a problem, please search for the posts explaining why this happens.Altering shoulders (smaller) when there is already a problem with divots is not to be done. There is already a lack of fabric.
Pleats mean there is is added width in the back panel usually from yoke to hem, and the excess is pleated in to fit the yoke.If you are trying to get the waist suppressed then darts are a choice you can make.Back Pleats and back darts are not used together in a shirt.Get a tape measure or get someone to measure you.