What is significance of low free T3 (liothyronine) and free T4 & normal tsh?

Hypothyroidism. Some scientific studies show that the optimal range for TSH is 0.8-2.1 in fact a TSH >2.5 is associated with Insulin resistance, as the TSH increases (above 2.5) the LDL goes up and the HDL goes down. There are countless patients walking around with undiagnosed hypothyroidism because the normal range of TSH is way too broad.
You are hypothyroid! Most doctors rely way too much on a high TSH to diagnose hypothyroidism but many who are hypothyroid (and low T3 and T4 mean you are hypothyroid for sure) have a normal TSH. See http://tinyurl.com/nrww2qg for a thorough discussion of the many very common conditions that render TSH unreliable. Please ask you Dr. to check thyroid antibodies as most who are hypothyroid have thyroiditis.
Not sure if any. The TSH is normal so it might be a variation of normal or euthyroid. It also might be a developing thyroid condition, but there would be symptoms, like fatigue. It would be wise to see your doctor to follow up.