It would have been better to have a two year deal anyway.
If he turned out to be below par, then you have two options in the second year.
1. Assuming he was being paid something around £1,200-£1,500 approximately per week, try loaning him out to a League Two club for a season, at 100% of the wage, as probably around 70-80% should be able to afford that kind of wage, or a Conference club for around 40-50% of the wage, to save money.
2. He gets released after 1 season, but being 19 he'd get paid half the remaining contract money, not the whole lot, so you save something at least.
These options would allow you to cut your losses, if he did turn out to br sub par.
Riht now the unfortunate thing is, the signings are not coming with long term guarantees. Cathalina and Wood on 1 year deals, Labadie and Showunmi on 2 year deals.
Personally I'd like to at least see a signing come in on a 3 year deal, just so there's a little more of a long term progression style ethos to the squad, because at the moment, trying to build for the future will be hard for the club, in lieu of signings being potentially good and not being around long enough to even garner a quality fee, because if a player like Labadie proved to be top notch, in 18 months from now he could walk on the Bosman ruling, with little more than possibly some compensation for Tranmere, which I doubt would even cover more than 50% of a transfer fee they could get, were he signed for 3 years and being bought instead.
Given what Jason Koumas was bought for some years ago, even if Labadie got offered something more high level, Tranmere wouldn't be being greedy, if they could expect £750,000-£1,000,000 for him, half way through a three year deal.
Frankly to get something potentially mediocre like £300,000 on a Bosman componsation package, after 18 of the current 24 months, would be a minor insult to Tranmere, but without the security of at least another year on peoples contracts, they will struggle if they lose good players, to get equitable fees, when they are being obtained via a Bosman ruling not a regular Transfer scenario.
All in all, the signings, (including Neilsen), are very positive, but as for a long term building programme, it is going to be hard without any players taking 3-5 year deals.
Yes the risk of long term signings being mediocre could occur, but that's a risk for anybody, (the aforementioned 2 options could still apply), but at least having a free transfer that turned out to be mediocre, is better than a £30,000,000 Ukranian, that could lose 1/3 off his cost within 10 minutes of penning the contract and you would struggle to sell for even half of that cost.
Though hopefully one day Tranmere could be a club famed for it's £30,000,000 signings, but by then I think you might possibly see the advent of 1/2 billion pound footballers, on half a million a week.