As brass instruments are all made of metal, with regular maintenance, care, and cleaning, the investment in a quality professional instrument - which includes all of those you've listed - is one that pays dividends in terms of performance outcomes, student enthusiasm, and can last a considerable length of time.
Regarding the trumpet - I prefer Schilke instruments, however, for bulk purchasing, and indeed for many professionals, the Xeno trumpet models you've outlined are exceptional instruments, well balanced, and have a consistent manufacturing quality, paired with durability, and ease of access to repair, part replacement, maintenance, and are on par with most professional Bb instrument lineups.
In terms of details for your superiors, I'd suggest emphasising the industry standard aspect, and quality aspect of the instruments you've proposed, as they all fall within reasonable categories, and are not unusual - these instruments are consistent with quality instruments, and advanced performers, and on par with, or exceeding, most comparable schools / programs in your school / program classification.
I can't speak to the Tuba situation, however, for your trombone and euphonium models listed, those are both industry-standard, quality instruments, that again meet or exceed the same criterion I mentioned above - their popularity, universality, and familiarity among instructors of a variety of backgrounds (orchestral, wind, marching, etc.) will make sure that over the long term, and the growth of your program, those instruments are able to meet the needs of current and future players, and educators.
Overall, an excellent and well balanced list! Good luck!