Sorry, your pictures are way too big to be able to view properly.

I've re-sized one just to answer your question re temple flaps.

The temples are the area of hair where I've marked them.
As you get older and hair thins, this area can also thin & recede, moving back towards your ear.

People use temple flaps to reinstate the hair in that area.

From what I can tell in your pictures, this isn't a problem for you, so in my opinion you don't need temple flaps.

The area that concerns you is where there is recession either side of the front hairline.
I have to say that your degree of recession looks perfectly normal for a man of your age.

If the hair on the rest of the head is still ok, then people use 'front partials' to fill in the gaps.
These can be 2 small pieces or one larger one that just goes along the front of your hair, evening & thickening up the hairline & filling-in the recession.
Do a forum search for 'front partials' to find out more.

If the hair on the top of your head is also thinning, then people use what is known as a 'topper'. This replaces all the hair from the crown at the back to the hairline at the front and down at the sides to as far as you need it.

A 'cut-in' is simply a haircut. Its when you have the new hair cut to blend in with your natural hair.

I really think you need to do MUCH more reading and searching before deciding to go down this route.