What's your question? Ask

Those stems from the bottom are actually a totally different plant! I notice that you also have some of the portulaca growing with the grafted moon cactus in the back!

What you can do (I wouldn't chop it in half) is take a leaf from the bottom, and set it next to the plant in the soil. It will eventually root, and grow a new shoot to become its very own plant! You can also wait until it send up a pup beside it. They will be able to be separated off and rooted separately as well.

The reason that your Echeveria is getting so tall may be a lack of light. These plants are suited for full sun. This means at least 8 hours of direct sun per day. The more the better.

There are many types of Echeveria. They all have very similar care. This article will help: https://www.gardeningknowhow.com/ornamental/cacti-succulents/echeveria/caring-for-echeveria-plants.htm

I could not locate it among the New Jersey common weeds, but I feel it is a weed. But if you like it, leave it be! For an ID, call your local extension agent or email him/her a photo. I bet they can identify it.

https://njaes.rutgers.edu/weeds/search.php

If your lowest temps are 57 then succulents may slow down their metabolism during the coldest months, but not necessarily go dormant. You can reduce watering to maybe once or twice a month, depending on the soil and how readily it dries out. Use a soil moisture meter to take the guess work out of when to water.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/succulent-plant-info.htm

This depends. If it is a seedling, then it could take a few years. If this is from cutting, then it can flower at any time that the conditions are proper. This can be hard to achieve unless you keep the plant exactly as it needs to be kept. This article will help you to care for them so that you might get some blooms one day: https://www.gardeningknowhow.com/ornamental/cacti-succulents/huernia/growing-lifesaver-cactus.htm

Too much direct sun can cause the leaves to scorch and drop. Perhaps you can set them near the window but not right in it. You can water them sparingly if the leaves are shriveling.

https://www.gardeningknowhow.com/ornamental/cacti-succulents/portulacaria/grow-variegated-elephant-bush.htm

It is definitely a succulent, most likely a type of sedum and it looks a lot like Sedum sediforme. Here is information on caring for succulents:
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/care-for-potted-succulent-plants.htm