The fact that the Chairman of one club has grave concerns for the future of his club should Hearts succeed in getting compensation should be of no relevance to the Arbitration process and his testimony an irrelevance.
The Arbitration process is to decide the legality of the process leading to Hearts, Partick and Stranraer being relegated and ultimately the legality of that relegation. As such the impact on others is not relevant.
Importantly Hearts are not actually claiming compensation. Their claim is that the relegation is illegal and, as such, that they should be reinstated. If they win they stay in the league they were in and the promoted teams do likewise and, sadly for them, miss out on promotion. They didn't, however, win promotion so technically would lose nothing.
Hearts and Partick's £10m is the amount relegation will cost them and if the Arbitration goes in their favour and the SPFL don't want to tell the previously promoted clubs that they got it wrong then that's the compensation the league would need to pay for Hearts and Partick to accept relegation despite the Arbitration going their way.
Notwithstanding that none of the others had any grave concerns about the impact their vote would have on the relegated clubs and were probably just glad it wasn't them. Compensation (rightly or wrongly) spreads the cost among 42 clubs as opposed to 3 clubs bearing the brunt.
Ideal scenario - Arbitration finds in Hearts and Particks favour, there is no promotion and no relegation and no requirement for compensation for anyone. The SPFL may, as other countries have done, make a nominal compensation payment to clubs that have missed out on the opportunity to win promotion through the league or the playoffs.
I'm also fairly certain that the panel conducting the Arbitration, despite what people have alluded to, do not have authority to force reconstruction. They may make a recommendation to that effect but I would assume that they would want to avoid that as that brings further complications. Can it be organised and fixtures agreed in time, is it permanent or temporary, if temporary how do you get back to the original format, how do you decide what the structure will be and how do you decide which teams go up from those in the playoff places? Don't think they'll want involved in that at all and it's not part of their remit.