The experts challenged the Scottish Government's insistence that it could negotiate "a smooth transition to independent EU membership" in 18 months, but all agreed that interim transition arrangements are likely.
EU members will not be "the slightest bit concerned" if Scotland wants an opt-out of the Schengen passport-free travel area and while a share of the UK's budget rebate would be "difficult", Scotland could get other rebates, the experts said.
The witnesses were giving evidence to Holyrood's European and External Relations Committee.
The notion that Scots will be "thrown out of the EU as citizens" is "alien" to committee convener Hanzala Malik, a member of the Labour Party, which is leading the Better Together campaign.
Laura Cram, professor of European politics at Edinburgh University, said: "A general preference for continuity within the EU machine is what we have seen historically when there are transitions.
"While we are talking about a lengthy, lengthy period of time, potentially, until all of the ends are tied up and a final membership package agreed, the notion that Scotland would somehow be out in the cold and floating in that interim period, even if it were to come entirely as an applicant state, would be considered unusual in the EU context.
"The general approach has been to agree transition arrangements.
"I think lawyers will come up with a compromise. It would be surprising that it would be in the interests of anybody to throw everything up immediately and not find some kind of working relationship that could work in the interim."
Dr Paolo Dardanelli, lecturer in comparative politics at Kent University, said: "I personally find the reframing of membership not unreasonable as a scenario, because it would be very problematic to expel Scotland following independence.
"So, the course that the (Scottish) Government has charted I don't find unreasonable, but it would be based entirely on negotiations and agreements with other member states.
"It seems to me like there is a bit of a game being played and a number of nationalist parties around Europe want to use the argument to direct member states to shift the politics of independence within those prospective states.
"The European institutions don't want trouble as much as possible, so the line of warning that 'if you leave, you will be outside' is played up precisely to that effect.
"I'm not entirely sure that is actually what view will prevail if the situation actually presents itself."
Professor John Bachtler, director of Strathclyde University's European policies research centre, echoed Dr Dardanelli's view.
"There is a lot of scope for mischief-making," he said.
"A number of member states have an interest in not making it seem like a smooth and easy process, so that would prolong certain aspects, possibly, of negotiations.
"But I do think there would have to be some bridge, some interim arrangements."
Scotland probably will have to apply as a new state but "with transition arrangements that would tide Scotland over until the requirements had been fulfilled," he said.
David Crawley, a former career civil servant and European negotiator, agreed that Scotland will probably have to apply as a new state, a process that has historically taken between a year and 14 years.
But he added: "I think the consensus of this panel is that there ought to be a set of interim arrangements agreed at some stage in this process which one would hope would protect rights.
"We don't know that, there are no guarantees and there are risks, but that is what we would hope."
Mr Malik said: "The panel today has opened my thinking up more. David, in particular, hit the nail in that there is a lot of risk in a lot of areas that we will have to face.
"This notion that we are going to be thrown out of the EU as citizens is alien to me because you are either a member of the EU or you are not, and in the absence of an agreement between Scotland and the EU we are definitely out, and it will be our choice rather than the EU's choice."
The Scottish Government insists that it will keep all of the UK's existing EU rights, including its opt-outs of the euro and the Schengen passport free-travel area, and a share of the UK's budget rebate.
Mr Crawley said: "I don't think anyone will be surprised or in the slightest bit concerned if Scotland wants to retain the Schengen opt-out, which is fairly consistent with the position that Ireland currently has. I think the most difficult areas will be fisheries and the rebate."
Mr Bachtler said: "It's very difficult to see a scenario where other member states would agree to our application for the rebate because the UK is constantly isolated in almost every budget negotiation.
"What would be more reasonable would be for Scotland to benefit from the more generalised correction mechanisms that Austria, the Netherlands and Germany benefit from, which don't have a permanent status but have to be negotiated every seven years. That is the most likely scenario."