Is ADA in my offer pool still staked?

YES!!! Any ADA in your offer pool (currently not having any loans accepted for it) is still sitting in your wallet and thus receiving your stake rewards. As soon as the loans are accepted, the ADA leaves your wallet, though, as it's now part of the smart contract transaction until the loan is either repaid or defaulted. Repaid ADA is put back into your offer pool, meaning it's again staked!

In the example below, we have 48 ada and 131 in our offer pool.

If I look this up in Cardanoscan, we will see that there's 179 total staked ADA