Mr.nazerath, 215/60/16 & 215/55/17 got plenty of type of tyre in the market
Is wise to switch to 215/55/17 size now since your car still got long way to go.
just few point to take note :
please go for Quality tyres and rim as you mentioned Safety and Petrol(subjective) is priority
careful when selecting rim that some will tell light weight (I am against this if strength of the rim is in doubt and compromised)MPV is not salon car
If you can get the Original Estima / Alphard will be good otherwise look for something Branded which usually more reliable.
Tyre size already known is 215/55/17 and mentioned many in the market ,again go for reliable brand like your pref yokohama also
bridgestone / Michelin/ Pirelli /continental etc are all
selecting the want tyre is sometime is really headache .
I suggest you leave it to your regular shop to share with you .