The ALT is a liver enzyme and can be elevated with stress, injury, or in many cases is elevated in conjunction with hypothyroidism. This is a very common finding in hypothyroid dogs. I am not concerned at all about the platelets being slightly elevated. The albumin being elevated and the platelets slightly elevated point toward mild dehydration.
I would suggest rechecking her liver values in 1 month after she is being treated for the thyroid condition to see if there has been an increase or decrease.
Please let me know if further assistance is needed.