Did anyone else have theirs arrive reeking of cigarettes??

Yes, the one I purchased also had a strong cigarette odor to it. I aired it out in my garage for a week before putting my dog in it. This booster seat is not very sturdy. It’s made very flimsy. I should have sent it back.

Does it have a friendly strap to prevent the dog from jumping out while driving?

SWIHELP DOG CAE SEAT Inside the chair, there is a leash with a hook. This leash can be hung on the collar of a pet dog or cat so that your pet will not jump out when it is naughty.

It has a strong oder, can it be washed?

Yes, it can be washed, the material is really easy to wash. About the odor, when I took it out of the package there wasn't a BIG odor. It smelled little like plastic but the odor when away once I put it on my car (roll the windows a little so it can ventilate).

Does this have seat belts to attach to pets harness? Or is there a way to feed thru an existing seat belt?

No it does not have belts. There is not place to feed it through the seat belt. There are three straps, one with a hook to attach to the dog's collar to keep him/her in the seat; with a strap to place over the back of the front car seat, and another one for possibly placing over the back of the front car seats if the dog is riding in the back of the car. The car seat is not very sturdy. The strap with the hook is actually quite long. It will not keep your pet in the seat. Luckily my dog sleeps during car rides. It's for fashion not protect.