Yes, You can do it.
Your moderator told you about the "O" rings being industry standard. Your hose material also is Industry Standard for refrigiration system.
When you have a leaking hose, don't throw away the most expensive part, the fittings; take it to a hose repair shop and have the hose material replaced using the fittings again.
I've done this for years and with out one failure.
As for the oil in the York compressor, yes it has a crankcase and the back plate with the fill plug must be in the proper position depending on the mounting of the compressor (vertical or horizontal).
If my memory hasn't failed over the years of York useage, the oil is Refrigiration 525 weight. If the compressor is noisy resulting from worn bearings, you may consider using refrigiration 1000 weight.
If converting to R-134a, the kit comes with a compatable oil charge. If you have lost oil through a leak, put in an additional Oil Charge.
Possibly another member may add to these hints.
Happy Trails Beep Beep from The Spiderman in Houston!!!