CRM first, marketing/projects second, analytics third.
Resist the forklift approach. Phase 1 moves CRM in 6 to 10 weeks. Phase 2 consolidates marketing and projects in weeks 10 to 16. Phase 3 rebuilds analytics in weeks 16 to 20. The phased approach catches issues earlier and keeps the business running. Teams who try to migrate the whole Zoho stack at once tend to see a disruption spike that compresses the ROI case.