Applying the parameters seems to have worked. However, its only visible in the get_witness return from beem. Steemd and cli_wallet only show the default values for the new witness properties.

>>> Witness('guiltyparties').json()
{'created': '2017-09-02T19:08:24', 'props': {'maximum_block_size': 65536, 'sbd_interest_rate': 0, 'account_subsidy_decay': 3307750, 'account_subsidy_budget': 10000, 'account_creation_fee': {'precision': 3, 'nai': '@@000000021', 'amount': '3000'}}, 'virtual_position': '332713497082428886940084539883832223718', 'url': 'https://guiltyparties.com', 'sbd_exchange_rate': {'quote': {'precision': 3, 'nai': '@@000000021', 'amount': '995'}, 'base': {'precision': 3, 'nai': '@@000000013', 'amount': '877'}}, 'hardfork_time_vote': '2018-09-25T15:00:00', 'owner': 'guiltyparties', 'last_aslot': 26416440, 'last_work': '0000000000000000000000000000000000000000000000000000000000000000', 'hardfork_version_vote': '0.20.0', 'virtual_scheduled_time': '377124827208063661343994537', 'pow_worker': 0, 'running_version': '0.20.3', 'votes': '8974839125598439', 'last_confirmed_block_num': 26322205, 'last_sbd_exchange_update': '2018-09-28T00:00:06', 'virtual_last_update': '377123983864831254948498363', 'total_missed': 105, 'signing_key': 'STM7FGmbPEooM5xbME7F2WUG41zGAh6WPzvHMQvTfABEHKfyuGUu7', 'available_witness_account_subsidies': 0, 'id': 14581}