For the first question, yes, provided the procurement process complied with the requirements specified in the Procurement Standards in 2 CFR Part 200, the Good Faith Efforts to encourage participation of small and disadvantaged businesses described in 40 CFR 33.301, and the compensation that you intend to charge to the grant for individual consultants (if any) complies with 2 CFR 1500.10. Please refer to the Best Practice Guide for Procuring Services, Supplies, and Equipment Under EPA Assistance Agreements, which is incorporated into the CCG NOFO as well (See Appendix G).
And yes, this requirement applies to engineering contracts as well, although for architectural and engineering (A/E) services you may use a qualifications-based competitive procurement as long as the requirements in 2 CFR 200.320(b)(2)(iv) are met. EPA also recognizes that geographic preferences may be used as provided in 2 CFR 200.319(c). Note that EPA takes the position that qualifications-based and geographic preference procurements may only be used to acquire services such as the development of building specifications that must be performed by a licensed A/E firm under state or local law.