Parallel TPS54260 outputs

If freewheeling diodes are used instead of SR (synchronous rectifier), outputs in parallel operation should be ok. If SR is used, the parallel will be in question and likely causing problem.

If using freewheeling diodes, although the parallel is ok, the current sharing ratio may not be 50%-50% if two in parallel, as there is no active current sharing mechnism based on the datasheet. The converters will share the load currents in sort of droop regulation which won't be able to make good sharing ratio and the ratio will be varying part to part and also varying with temperature change. 

Now if 10A load is expected, more than four converters, at least five, will have to be in parallel as the current sharing ratio won't be 25% each if only four in parallel.