I like the concept. The illusion comes from the differences in the size of the bottle neck and opening in comparison to the size of the object in the bottle. So what your looking for is that the finished lighthouse is larger than the opening. This requires splitting the light house into pieces and reconstructing those pieces in the bottle. That process get's tricky and there's no one way to do it.
I have seen some people that take the finished project and cut it into pieces and reassemble it in the bottle. I think thats a difficult method. The problem with cutting a finished piece is the saw often cuts out something like a half milometer or less and the pieces don't come together perfectly leaving a seam, which detracts from the illusion. In bottle art every millimeter counts.
The other method is to build separate individual pieces that are fit together by pegs or magnets or string. When finished these pieces will fit in the bottle neck individually, come together in the bottle and have little to no seam lines and as a whole be bigger than the bottle neck.
If I were starting out on this I'd do a bottle with two pieces fit together with pegs. Once I got the hang of that branch out to four pieces. There are ways with ships in bottles to hide seem lines when spitting a hull to fit a ship in a bottle. For instance using the channels to cover up the split places making the hull seamless. I'd have to study light houses to find similar lines where seams could be hid. Look for that though. A lot of lighthouses have a wider top and a seam could be hid where the base and top come together. Another method maybe applying paint over seams ones the light house is in the bottle. That can get really tricky but it's not impossible.
I would look at things like houses built in bottles or steamboats. We have a couple build logs that did something like that. Arturs build is a good example.