What is the difference between a Religious Person and a Spiritual Person?

Probably no difference. The two words are used interchangeably. It is perhaps better to specify - they are Christians, or they are Jews, or they are Atheists, etc.

Can you be a Religious Person and not be a Christian?

Ah, Hindu? Muslim?
Many Christians are not Christians, ie, Christ-like. A legal religionist can never lead souls to Christ.

If being "Christian" is Christ-like, then can a Muslim be Christian? Then also, is a Hindu "who refuses to step on an ant" more Christian than a Christian?

We could also ask - What is the difference between being saved and being lost?

Labels like religious and spiritual are somewhat fuzzy..
The usual connotation of "religious" tends to be interpreted as a formal compliance to religious rituals and rules, while the connotation of "spiritual" tends to be interpreted as being emotionally and more feeling oriented to things considered spiritual. Both words can be applied to define members of pretty much any religious or spiritual movement -- Hindu's New Agers, Muslims, Christians, etc. etc.

However, a genuine Christian is a follower of Christ -- Christ is their Savior, Friend, Guide, Example, Helper, Sustainer,, in Him is their hope, trust and faith. and they follow Him, study His life, commune with Him, and live for Him. To be a genuine Christian is to be in a vital relationship with Christ.

That is a good question and is best answered with the apt proverb: the race is not for the swift but for those who endure to the end.

Spirituality, that which recognizes the overarching Divine will of God, is what really and finally matters. Religiousity is merely the forms and ceremonies and formal statements that seek to anchor the soul to that reality. There are many, a vast array, that purport to satisfy the criteria for religion, but the extent to which they matter is left up to each person.

Here is how Jesus put it: "Woman, believe Me, the hour is coming when you will neither on this mountain, nor in Jerusalem, worship the Father. You worship what you do not know; we know what we worship, for salvation is of the Jews. But the hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth; for the Father is seeking such to worship Him. God is Spirit, and those who worship Him must worship in spirit and truth." John 4:21-24

Notice how He strips the dueling "religions" from the core principle of a single spirituality: that which is true remains.

Love this.