Praise be to Allah.
It is permissible for the one who is doing ‘umrah, after he has circumambulated the Ka‘bah (tawaaf) and gone between as-Safa and al-Marwah (sa‘i) to delay shaving his head or cutting his hair, on condition that he does not do any of the things that are prohibited whilst in the state of ihraam, such as covering his head, putting on perfume, trimming his nails or any of the other prohibited actions, until he exits ihram following ‘umrah by shaving his head or cutting his hair. For more information, please see the answer to question no. 138178.
But if he has shaved his head or cut his hair, then he has in fact exited ihram following his ‘umrah, regardless of whether or not he has changed out of his ihram garments, and it is permissible for him to do all of the things that had been prohibited to him because of ihram.
With regard to hastening to change his clothes or otherwise, that depends on his circumstances and what is easiest for him. However it is preferable for him to take off the ihram garments and put on his usual garments, so that he will be able to offer his prayers and go about all of his business comfortably, with no difficulty.
The Sunnah on Friday is for the Muslim to do ghusl, put on perfume, and wear his best clothes, because the Prophet (lettings and peace of Allah be upon him) said: “Whoever does ghusl on Friday, puts on his best clothes, puts on perfume if he has any, then comes to Jumu‘ah and does not step over the people’s necks, then prays what Allah has ordained for him, then listens attentively when his imam comes out, until he has finished the prayer, it will be expiation for whatever came between it and the previous Jumu‘ah.”
Narrated by Abu Dawood (290). Classed as hasan by Shaykh al-Albaani in Saheeh Sunan Abi Dawood.
Based on that, it is better and more appropriate, if there is no great difficulty involved, for him to hasten to exit ihram following his ‘umrah, and to prepare for Jumu‘ah prayer by doing ghusl, putting on perfume, and putting on his best clothes.
It is mustahabb for the worshipper to be close to the imam during his khutbah, because the Prophet (blessings and peace of Allah be upon him) said: “Whoever does ghusl and causes his wife to do ghusl, then comes early, walking and not riding, and sits close to the imam, then he listens and does not engage in idle speech, for every step he will have the reward of one year’s fasting and praying qiyaam.”
Narrated by Abu Dawood (292); classed as saheeh by al-Albaani in Saheeh al-Jaami‘ (6405)
Ibn Qudaamah (may Allah have mercy on him) said: It is mustahabb to be close to the imam because the Prophet (blessings and peace of Allah be upon him) said: “Whoever does ghusl and causes his wife to do ghusl, then comes early, walking and not riding, and sits close to the imam, then he listens and does not engage in idle speech, for every step he will have the reward of one year’s fasting and praying qiyaam.”
End quote from al-Mughni (2/103)
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: Undoubtedly sitting close to the imam, in al-Masjid al-Haraam or elsewhere, is better than being far away from him.
End quote from Majmoo‘ Fataawa Ibn ‘Uthaymeen (13/30).
Based on that, being close to the imam is better than being close to the Ka‘bah.
One of the unique characteristics of al-Masjid al-Haraam, is that it is the best of mosques and the greatest in reward for the one who prays in it, because the Prophet (blessings and peace of Allah be upon him) said: “One prayer in al-Masjid al-Haraam is equal to one hundred thousand prayers offered elsewhere.” Narrated by Ibn Maajah (1396); classed as saheeh by Shaykh al-Albaani (may Allah have mercy on him) in Saheeh Ibn Majah
Another of its unique characteristics is that Allah has made it secure, as He, may He be exalted, says (interpretation of the meaning): “And (remember) when We made the House (the Ka‘bah at Makkah) focal point for mankind and a place of safety” [al-Baqarah 2:125].
For more information, please see the answer to question no. 3748
There are other rulings having to do with al-Masjid al-Haraam and the Haram (sanctuary) area in general, which the scholars have discussed in their books on the basis of the texts which speak of that. For more information, see the book entitled Ahkaam al-Haram al-Makki by Shaykh Saami ibn Muhammad as-Suqayr, in which he discusses issues and rulings having to do with the sanctuary of Makkah and al-Masjid al-Haraam.
And Allah knows best.