Rte Christmas Crossword - Stuck On Five

[Echobongo]

18a Santa's team goes all for one and one for all! (4) ???R Is it Four or Deer? But why?

21a It's what we must out-survive, even without Victory in Europe (5) V???S

22d Most ancient Roman that roamed before Rome? (5) ??M?S

15d Quick and soft, musically, put in unscored lettering (3) P??
31/3d Only the bronze-medallist of the magi, maybe. At any rate, that's the clue (5,4)
Least ?I?E

[bobbinwales]

18 deer (plural of deer)

[zebo]

21 Virus, take VE out of survive

[bobbinwales]

virus

[cashier]

21 Virus Survive without ve

[emeritus]

22 Remus

[bobbinwales]

remus?

[cashier]

22 Remus?

[bobbinwales]

least wise

[zebo]

31 Third King?
22 Remus ?

[bobbinwales]

A think leastwise means same as anyway/anyhow/at any rate

[Echobongo]

Thank you all, great answers

[weecalf]

Third base maybe ?

[emmie]

15 maybe

Più

(Italian: 'more'). A term that can preface an instruction to mean 'more of'. 'Più vivo', meaning 'more lively', or 'Più lento', more slow.