What's your question? Ask

Curbits normally do not transplant well, but you can try to save it. This article will help: https://www.gardeningknowhow.com/plant-problems/environmental/learn-how-to-avoid-and-repair-transplant-shock-in-plants.htm

No. Leave the flowers alone. When they are no longer useful to the plant, they will fall off on their own.

Like tomatoes, peppers, and squash, watermelons can also be affected by blossom end rot. This condition happens due to a calcium deficiency. Calcium helps a plant create a stable structure. If a plant gets too little calcium while the fruit is developing, the end result is what you're experiencing. There are a few things you can try for blossom end rot treatment.

Water evenly, not too much or too little. Add a low nitrogen fertilizer to the soil. he s for optimal calcium uptake. Add lime to balance the soil’s pH if it is too low, (should be between 6.0 and 6.5). Add some gypsum to the soil for additional calcium. In addition, remove affected fruit and use a calcium rich foliar spray on the plant.

It won't hurt the plant to remove some of the shoots, but you might be better off if you remove some of the female blooms. The watermelons already formed will grow larger with less competition from other fruits. You might find the following article helpful: https://www.gardeningknowhow.com/edible/fruits/watermelon/growing-watermelon.htm

It sounds like it has blossom end rot. This article will help:
http://www.ces.ncsu.edu/depts/pp/notes/oldnotes/vg19.htm

Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/fruits/watermelon/pick-a-watermelon.htm

If the tendril is green, you should wait to pick the melon. Harvest when the curled tendril closest to the melon on the vine begins to shrivel and dry up.