If I have accounts linked via w3ndi and later delete my web3name, when someone else claims that web3name would my accounts still be linked to it for sending and receiving funds? 

No. Each IPFS file which holds the records of accounts linked via w3ndi has to be signed with a DID in Sporran wallet. Therefore, the endpoint towards that file is connected with that DID. If the web3name was released and then reclaimed by another user, the  web3name would then have a different DID and the relation to the old record on IPFS would be broken.

You can also unlink your web3name and addresses via the 
w3ndi website
. Note, however, that the minimum linking period is six months.