RSI, & MFI; are oscillators. IMO Good for support of trend.
OBV & CMF are volume indications good for pressure expected when a move starts.
Choose 3 indicators, one trend, one momentum & one volume. Your watching for trend entry, will retail support your decision and how strong to expect any move you enter, will be. My choices to fulfill these are DMI, StochRSI and CMF.
OBV being less useful then accumulation/distribution, (A/D) which is in turn less useful the CMF. Because A/D was an improvement to OBV and CMF an improvement to A/D. I always use CMF.
But I do recommend all to try different indicators with their personal trading styles. There may be better fits then my fav's for your style.
Try them see how they work! Always do what works best for you. Not someone else.