Garden placement question

This will be our first year planting at this house. The previous owners had a garden behind the garage, but I'm questioning it's placement. That area does get the most sun as we have two 100 year old trees that lead the backyard to be mostly shady. The garage however is in pretty rough shape and has lead paint that chips off quite frequently. The garage also sits higher than the garden so water naturally flows from the garage to the garden. I worry about lead in the soil leaching into our food and having the boys working in the garden b/c of the lead--is this as serious an issue as I think it is?

One other option is to place the garden on the south side of the house, but the area is next to the oil intake for our furnace and my partner pointed out that the area may not be the best b/c there is the possibility of past oil spillage.

Our only other option is the front of the house--which I kind of like as I feel we would foster better community ties gardening out by the sidewalk That's the west side of our house so it's shady in the morning up until about 10AM--will that be OK? It gets all the hot afternoon sun and there are no big trees.

Can you tell I'm a garden newbie