I would recommend finding the correct fork, issuing a checkpoint past the hard fork, and then reissuing the wallet. This was my strategy with HYP, and it worked well.
Just my .02 btc...
Yea it worked for ADN also.
It can not work if majority of network are "cancer" nodes which is the case here. Unless there is filter for all older versions of TEK client there is very little chance legit nodes will
be able to connect to other legit nodes - especially important with pools - but once they manage to do that there will be major orphaning of others' blocks. I'm not sure how many
blocks in past can TEK network reorganize but it is almost a must to stop being polite to morons who are still using abandoned wallets and kick them out from network until they
finaly upgrade. Flappycoin did that successfuly, check it's source-code.
This is a perfect example of Hal-Finey (or it is Sybil?) attack, where adversary can cause major problems by intentionaly creating and connecting many "cancer" nodes to network.
That is the reason why Bitcoiners are afraid of continualy dropping number of legit full nodes on Bitcoin network. If legit nodes can not find other legit nodes it is basically game over.