Ex-Tory MPs Neil Hamilton and Mark Reckless are among the candidates chosen to top UKIP's assembly election regional lists, BBC Wales understands.
It follows a row amid claims they were being imposed on Wales by the party nationally.
Party members in Wales were asked to vote on a list approved by UKIP's national executive committee (NEC).
Experts suggest UKIP could get nine AMs elected via the regional lists based on a recent ITV poll.
Forty of the assembly's 60 members are elected on a constituency basis, as in general elections.
The other 20 are elected in a second vote via regional lists, under a proportional system designed to give parties a share of seats that more closely reflects their share of the total vote across Wales.
Regional lists are seen as UKIP's best hope of winning its first ever seats in Cardiff Bay.
Mr Hamilton was chosen to head the regional list for Mid and West Wales, while Mr Reckless will be the lead candidate in South Wales East.
UKIP Wales leader Nathan Gill will top the party list for North Wales, with NEC member Caroline Jones in South Wales West and former council candidate Gareth Bennett in South Wales Central.
The candidate lists are due to be ratified at a meeting of UKIP's NEC later on Monday.
A Welsh Labour spokesman said: "After such a drawn out and divisive process, it's pathetic that all UKIP are able to offer the people of Wales are a gaggle of failed Tories."
Welsh Liberal Democrat leader Kirsty Williams claimed UKIP had "no interest in standing up for communities in Wales", urging supporters of other parties to back the Lib Dems with their second vote.