I'd keep some of the higher level ones (L25+) for future Eeveelutions and leave it at that, unless you have an active need for any of the others. It's hard to trash high IV stuff but you gotta draw the line somewhere. Are you really going to power up and utilize that L8 96% Eevee? That's over 300 candy factoring in evolution and over 263k dust. I don't know the weather in Singapore but partly cloudy is fairly common where I live, high level/IV Eevee aren't hard to come by.
So many wonder Eevees. What to do with them?
Here is the list (IVs are A/D/S):
L30, 13/12/13
L26, 14/11/14
L26, 11/15/15
L25, 15/15/14
L20, 14/14/10
L18, 13/13/14
L15, 14/13/15
L15, 14/11/14
L15, 13/13/14
L15, 13/13/14
L15, 12/12/15 or 13/10/15
L13, 15/14/11
L11, 15/14/11 or 15/12/13
L10, 15/13/13 or 15/14/12
L8, 15/15/13
Which to save for Leafeon and Glaceon? Which to try for Flareon with OH or Jolteon with TB? Which to walk for Espeon and Umbreon (not yet done the Celebi research)?
All name tricks used. Missed Eevee Community Day (so none with Last Resort). Main use for Eevee is to solo tier 3 raids with level 30 non-legendaries (so no low-IV weather-boosted ones). If I am poorly prepared for a new legendary, they can also fill my team.
My only L30 Espeon (12/15/14, Cn/FS) leads my Machamp solo team and my L30 Vaporeon (15/14/14, WG/HP) last saw action on Moltres Day (previously against Aerodactyl). Yet to power up my former-prestiger Jolteons and Flareons (except one with OH) as none are better than 87%.
Answers
You could save a few of the high level ones for trading, but unless they are really prime (96%+ and decent level), then they aren't worth much. Clearly the 98% at level 25 is a good one, I'd save that for Glaceon or Leafeon (depending on which is better) or Sylveon, if you have the patience for that. The rest are just cluttering up your pokemon storage.