Your favorites Jambiani

$40 is not a bad price for a transfer to Jambiani, saves you all the haggling with taxi drivers, and you may not even get them lower than that anyway.
Where you should go to eat depends on where you are, whether you will have some form of transport etc. I'm not all that familiar with Jambiani, but generally, resorts along the east coast tend to be quite spread out, so you will probably end up eating either at your own resort or the neighbouring ones, unless you have a car.
At very low tide you can walk along the beach or out to the reef (if you have proper foot protection), you can cycle along the the beach, all the way up to Michamvi if you feel energetic.
Many resorts with swimming pools will let you use theirs for a small fee or even for free if you eat at their restaurant, but whether this is a good option again depends on how close the closest resorts with pools are to yours.

There is only one hotel in Jambiani with a swimming pool, the Sau Inn. Never tried myself but for sure they'll let you use their pool.
My favorite restaurant is Kim's restaurant (Northern part of Jambiani) - excellent food.

The Coral Rock Bungalows have a small (infinity) swimming pool as well which is lovely.

gave some suggestions already: other thread about the Jam

plus agree with 2. about the food at Kims...., if you stay in the southern part - food at casa del mar is nice aswell...

no problems to walk on the beach during low tide, and bring a kite ! it's fun ....and always enough wind.

my personal opinion about pools : guys, you got the ocean ! please think about us in Jambiani having problems with the water+electric supply because the tourists want pools and ac....and the powerlines are not strong enough and the water is sometimes not enough for the villagers !
cheers
g