That should be fine, just check it all out before party guests arrive. There's a chance the lights may flicker (filament)/restart (discharge) when the pumps start. Not a lot you can do about that unless you change the cable.
It might also be advisable to investigate the type of circuit breakers you have on the 50A and 63A distribution circuits. Replacing a B50 & B63 with C50 and C63 respectively will help to ensure that start-up currents and short overloads do not cause any nuisance tripping of those, very important, distribution circuits. Your electrician will be able to advise on this, depending on the results of loop impedance tests on the cable.
It might also be advisable to investigate the type of circuit breakers you have on the 50A and 63A distribution circuits. Replacing a B50 & B63 with C50 and C63 respectively will help to ensure that start-up currents and short overloads do not cause any nuisance tripping of those, very important, distribution circuits. Your electrician will be able to advise on this, depending on the results of loop impedance tests on the cable.