I have used Winter, Field, Cereal Rye as a winter cover crop for somewhere around 45 years and have never had a problem with it regrowing when cut, or knocked down, before seeds formed. The Rodale Institute has done extensive work on crimping Winter Rye to be used as a mulch and the USDA has now found this process to be something worthwhile, I would suspect this would not be something they would promote if regrowth were a problem. Which to use will depend on how available one or the other is. If Eel grass is more readily available, and free, that is what you should be using. However, for others of us the Rye seed is more readily available even though we need to pay for it. Here is a link that might be useful: Crimping Winter Rye

I always bring my spikes in over the winter. I have a sun porch that I heat to stay above 40°. I love that the spike plants get huge! By the 3rd year, they're too big for a window box, but they're an awesome large accent plant in a BIG planter, garden or landscape. Easy to keep in the house too with a little sunlight. Inside, I water with rain water/melted snow to keep tips from yellowing from the city water.

People do keep fairly large plants indoors and not necessarily in the basement. A lot of your plants van be kept as regular houseplants and may not even need additional lights and might just be content with regular indoor lights. If I were you, I would rank them in order of preference and then start bringing them in one by one after I have found a spot or corner for them. I would leave the sunny space in the kitchen for the ones that need the most light/sun. You do not need a table to put them on, they all are fairly tall and will be happy sitting on the floor. Buy a bunch of wheeled things that are meant to be kept under large plants to facilitate movement. You could build a ramp or use a temporary ramp and get some help moving them. The majesty palms (I think) can live in any brightly lit corner, so can the sterltizia (look a little like bananas). The hibiscus and crotons need more light and can go in the kitchen. Chop off/prune the seasonals, they might regrow and adapt, at least the ones in the kitchen. If you have large living space, you could find a place for the palms etc. that don't need as much light. You could use table/floor lamps or existing lights and use full spectrum LED lights for the ones that need more light but cannot be accommodated in the kitchen. Anything you just want to overwinter but not enjoy indoors can go in the basement. The overly large seasonal ones like the potato vines may have to go or at least cut back quite a bit. Look for bugs before you move them in. Some people treat everything they move in with horticulture soap, oil, or bayer 3 in 1 to keep bugs out. I have found that if i bring them in after it has turned a bit cold, there are not that many hitch hikers, if any. But my plants live on a fourth floor balcony. I like to let the little garden spiders be and think they may be keeping any smaller bugs like aphids etc. in check. Good luck.

Consult your PB and ask if it's ok for it to be empty over the winter. Their structural engineer should be able to provide that information as well. My own structural engineer designs our pools so they can be empty through the winter. Generally, we will fill the pools at least 2/3 of the way up the shallow end wall. If your site has wet conditions or a high water table, I would consider filling it. Water actually will act as an insulator and it will protect the pool floor and up the wall at whatever water level you maintain.